I've been thinking of doing the same for my next sorc. This is the standard pure light build right? I see a problem with your resists, fast cast, and hit recovery though. I was thinking about using some Tal's to help those areas.
I guess you get some FCR from the echuta and Spirit, but I always like a faster cast than that. You'll be at 65-75%, past the 63% non lightning and 52% Lighting breakpoints which is probably the minimum. I'd see if its possible to get to 105% (non-light) / 117% (light) breakpoints. Even if you can't do that 78% will get you to another lighning breakpoint.
For your hit recovery, I'd really try to add 5% more somewhere (SC is easy) to hit the 60% breakpoint.
Resists look to be a big problem. You only have Mara's, Spirit and a torch to keep from hitting the -70% area. Even if both of those are perfect (really $$$) that's -20 overall. Add in an anni to get some more, but that will still leave you at zero (if your torch, anni and mara are all perfect. Realisticly you'll be at -20 to -10).
Depending on your level, Tal armor is worth concidering. It comes with a fixed 88 MF. You could also squeeze out the 3 piece 65% MF bonus (belt, armor, amy). Tal armor even comes with some nice resitances and the Amy has some +life and mana.
Skulders = 110% MF (at level 88)
Gold Wrap = 30% MF
Mara or Tal Amy = 0% MF
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140% MF
Tal Armor = 88% MF
Tal Belt = 10-15% MF
Tal Amy = 0% MF
3 piece set bonus = 65% MF
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163-168% MF
Of course once your there, you could add tal orb for the -15% enemy lite resistance. You'll loose +2 skills when you sub out the orb, but you'll gain the +2 back on lightning mastery. You'll also find that the -15% enemy light resistance on Tal's orb would be much better than the +20% light damage on a Perf Eschuta. Suprisingly, Tal's orb with the rest of the set will also get you 10% more faster cast (50% total for Tal). Adding the Tal orb will also get you 25% more hit recovey. You can easily add 6% as a 2nd mod from a few sc's to get you to the 86% breakpoint.
If you've followed me to this point, you may also want to consider swaping the Shako for Tal Helm. You'd actually gain a skill (+3 for the whole set bonus vs. +2 on shako) which will offset the loss on the weapon. You will loose some of the +life and +mana on shako, but Tal Helm does come with some of its own, and there's a set bonus of +150 life. So you actually come out well ahead on life and just a few higher on mana (overall, see below). Loosing the 50% MF on Shako is tough - no argument there. You could keep the shako in inventory for boss kills. The big bonus's on the tal helm are the +15% resist all from the helm and +50% resist all from the complete set bonus. 65% resist all is nothing to sneeze at.
Let's see if I can sum this up (I'll exclude the inventory of SC's and sockets which will stay the same)
Orignal Set up
14 all skills (3 Eschuta, 1 Skulders, 2 Shako, 2 Mara, 2 Spirit, 3 Torch, 1 Anni)
20% Light Damage (Eschuta)
65-75% Fast Cast
55% Hit Recovery
340% MF total (excluding sockets and SC's - see below)
-15% Resist Fire (see below)
20% Resist Cold (see below)
20% Resist Lightning (see below)
20% Resist Poison (see below)
266 Life (see below)
352 Mana (see below)
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110% MF (Skulders at level 88)
30% MF (Gold Wrap)
40% MF (Chance Guards)
50% MF (War Tav's)
50% MF (Shako)
60% MF (2x P Nagels)
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-70% resist all base in Hell
+15% resist all (Anni - Average)
+15% resist all (Torch - Average)
+25% resist all (Mara - Average)
+35% resist Cold/Light/Poison (Spirit)
______
+132 Life (Shako at level 88)
+44 Life (+22 Vit on Spirit)
+10 Life (+5 Vit on Mara)
+20 Life (+10 Vit on War Travs)
+20-40 Life (+10-20 Vit on Anni, 30 average)
+20-40 Life (+10-20 Vit on Torch, 30 average)
______
+132 Mana (Shako at level 88)
+89-112 Mana (Spirit, 100 average)
+10 Mana (+5 Energy on Mara)
+40-60 Mana (+20-30 Energy on Eschuta, 50 average)
+20-40 Mana (+10-20 Energy on Anni, 30 average)
+20-40 Mana (+10-20 Energy on Torch, 30 average)
Full Tal Set up
+12 all skills (1 Tal Orb, 2 Tal Amy, 3 Set Bonus, 2 Spirit, 3 Torch, 1 Anni)
+2 Lightning Mastery
-15% Enemy lightning Damage (Tal orb with 3 other pieces)
75-85% Fast Cast
80% Hit Recovery
318% MF total (excluding sockets and SC's - see below)
65% Resist Fire (see below)
100% Resist Cold (capped at 75%, see below)
135% Resist Lightning (capped at 75%, see below)
60% Resist Poison (see below)
441 Life (see below)
359 Mana (see below)
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88% MF (Tal Armor)
15% MF (Tal Belt)
65% MF (3 piece set bonus)
40% MF (Chance Guards)
50% MF (War Tav's)
60% MF (2x P Nagels)
_______
-70% resist all base in Hell
+15% resist all (Anni - Average)
+15% resist all (Torch - Average)
+15% resist all (Tal Helm)
+50% resist all (Tal complete set bonus)
+40% resist Fire/Cold/Light (Tal Armor)
+33% resist Light (Tal Amy)
+35% resist Cold/Light/Poison (Spirit)
______
+60 Life (Tal Helm)
+44 Life (+22 Vit on Spirit)
+50 Life (Tal Amy)
+20 Life (+10 Vit on War Travs)
+57 Life (Tal Orb)
+150 Life (Tal set bonus)
+20-40 Life (+10-20 Vit on Anni, 30 average)
+20-40 Life (+10-20 Vit on Torch, 30 average)
______
+30 Mana (Tal Helm)
+89-112 Mana (Spirit, 100 average)
+42 Mana (Tal Amy)
+97 Mana (77 mana +10 energy Tal Orb)
+30 Mana (Tal Belt)
+20-40 Mana (+10-20 Energy on Anni, 30 average)
+20-40 Mana (+10-20 Energy on Torch, 30 average)
Conclusion - I'll go Tal's. I'm loosing 2 skills (except on mastery), and 28% MF, but I'm gaining Fast Cast, Hit Recovery, Huge Resists and Huge Life. Maybe I'm just more of a defensive person.
*You could also sub in an enigma to get almost as much MF as your build, one more skill, and lots of strength (to help wear the Spirit Monarch).
**Or largely forget MF on your armor and go Chains of Honor (+2 skills, +65% resist all, 25% MF). I think this would be a huge improvment on your original build. You'll loose about 100 MF, but gaining a skill and having maxed resists in hell will make it well worth it in my opinion. You'll see that MF% over 300% the whole deminishing returns thing really starts to sink in anway.