Lets say you do decide to go for max block on a sorc. then its best to use a whinstans guard, or an up'd Visceratuant sheild. and i would place an eld rune in them, for more block%.
they have much les str req. and better chance to block than SS.
Honestly, I don't think that you'll find it worth it. If you're using the Spirit Monarch, Chances are that you're not going to have another source of faster block %. This means that you're going to have about a nine frame block. Spirit gives 55% FHR, already putting you at a 9 frame recovery and 5% from 8 frames. Hitting 86% is quite easy to do for the 7 frame recovery, so while using a Spirit Monarch, it is usually just easier to take the blow and recover quickly and move on.
Also, the boatload of points you'd be spending in Dex would work well in vitality. You'll find yourself making the hit recovery animation less often if you have more health, so more points in vitality is always good.
Finally, there are very few things you'll actually need a shield to block. If you're planning for blocking for your teleporting, it's better to have a high vitality so you don't enter hit recovery animations. This allows you to cast while being hit versus entering block lock where eventually you'll get swarmed and can't cast.
No way blocking is better. you only need 237 for max block for ss at 99. If you put all into vit you only get about 600 more health cuz 1 vit is 2 life. Most of the time your teleporting that's the thing. If you teleport into the middle of a group of guys your done if you have max vit cuz sometimes they freeze. But with amx block you can block the hits. If your going against magic your usually far away anyways. Plus you will have damage reduce. 48 percent with enigma, ss, and shako. so you choose. 600 more health and crap block. or good block, good damage reduce. plus you can increase life with charms, that will be hard for dex...