i'm glad that the information helped
about the calculation, i could not get your result. let's do it step by step so someone can correct me if i'm doing something wrong...
first, Porius seems to have made a mistake by calculating the skill damage. +800% damage comes from synergies, which makes it 900% of the listed damage. at lvl 20, that's 4860-5229 (5044.5 avg) dmg for 9.6 seconds (blackbogs gives +5 to pdagger, but i don't have access to the dmg at lvl 25).
avg dmg/sec: 525.47, duration: 9.6s
Blackbog's
dmg/sec: 48.8, duration: 10s
Perfect Emerald
dmg/sec: 14.29, duration: 7s
Tal rune
dmg/sec: 15, duration: 5s
Total dmg/sec (we add all up): 603.56
Average duration of Blackbog's+Tal+Emerald: 7.33s
Total duration with pdagger duration added: 16.93s
Total dmg: 10220.3
of note is that, if we were to take out Tal from the setup, we'd have:
Total dmg/sec: 588.56
Average duration of Blackbog's+Emerald: 8.5s
Total duration with pdagger duration added: 18.1s
Total dmg: 10653.9
with only Blackbog's (Tal and Emerald removed):
Total dmg/sec: 574.27
Total duration: 19.6s
Total dmg: 11255.7 (1035.4 higher from the initial setup)
these numbers might be off by a tiny bit since i don't know where and how the game rounds numbers. i also used the average dmg from pdagger, Porios had used min dmg.
Edit: you cannot have both a Tal rune and a Perfect Emerald in Blackbog's Sharp. although a Cinquedeas can get 3 sockets, elite items will only get 1 socket from Larzuk.