If the OP is still checking on his topic im more curious as to the Elixir gun heal build he was running if he could provide a link. Me personally im using dual pistols and with 30 in alchemy and sigils of agony, bleeds stay at about 5-6 stacks and if i run with elixir U i can stack it to -9 if only for a brief second.
I do agree that it seems they drop off way faster than you can apply them, atleast at the higher stacking numbers