I thought they nerfed that a long time ago?
Which double boss fight are you having problems with? I found one to be really easy because one of the bosses moves really slow, so you can use movement to separate them and take them out...
The double boss fight with
was the only true hard fight in the game for me. My priority with this fight was hit both with sloth then weakness...then take out
as fast as I could. Hand cannon as many shots as you can to start and then focus everything. Once you drop one boss, it because stupid easy like all the fights.
Don't worry about living weapon. You should be able to drop one of the bosses in about 30 seconds if everything goes right for you.