wow this post takes me back a ways - when i first switched to saltwater i had that exact setup (picaso trigger and porcupine puffer) for about six months. I had no problems - none whatsoever. One thing could have played into it was the porcupine was about the size of of my balled up fist and the trigger was about 1/8 his size but they got along fine together in a 37. Also my porcupine was extremely docile.
thats all i got, good luck i'd say go for it.
regards
drew
ps one thing that was really annoying to me was i had to feed two different types of food, brine for the trigger and krill for the puff , neither would even look at the others food. kinda strange