to clarify:
if you are an infinity wielder, like nova sorc, spearzon, trapsin, +% lsd is better. (because with conviction your -enemy lr is already near capped for all monsters.)
If you are using hex bane or hex purge +% msd is better. (because it double dips)
If you are a sorc using enchant +%fsd is better. (double dips)
Poison necro with a deaths web, trang shield already, +%psd is better. (because with lower resist your -enemy pr is already near capped for all monsters.)
If you are tainted/bloodboil lock +%fsd is better.
but for fire chaos lock -% is better.
Amazing, thank you for clarification.