got a few pms to post screenshot and about how it works with assasin venom interaction so i'll explain it here (i personally use it as a fun setup on my spidersin, just a normal spidersin but i maxed venom so i can have a bit of fun also)

full venom damage applies every 0,4 seconds for the full duration of poison dagger + another 0,4 base venom duration
so if poison dagger lasts 4,8 seconds (5,2 seconds with venom) it will last 10,4 seconds in hell (with -100 poison length reduce everything has in hell)
dealing roughly ~ 106824 - 108928 damage over 10,4 seconds
pvp damage:
(107876 average * 0,25) / 6 = -4494 life in 1 hit vs 75 poison resist enemies (you 1 hit pretty much anyone except barb or druid)
heres about the setup im using(some charms may be 1 or 2 life off):
https://maxroll.gg/d2/d2planner/i18950ovnotice im not using any poison facets in gear (you can greatly increase damage with these giving over 5k damage extra per facet)