4-channel amp

Just a quick question for all you out there. Is it a dumb idea to use a four channel amp to power just 3 subs? I would only prolly use 3 of the four channels. For your info the amp is a PPI PC-4100 the old school one, and the subs are 3 JL Audio 12w6's also the old school ones. I figured I could wire 2 of them to 2 channels, and then the other bridged between the other 2 channels. I could also just wire each sub to it's own channel. Any thoughts on this would be appreciated.

If you put more power to one of the subs you will have to have seperate chambers per sub, or atleast the one with more powerdream it, build it, fiberglass it

All 3 subs are in there own chambers. The vehicle is a Suburban and the subs are right behind the second row seats. Their placements are 1 behind each seat(have rear buckets) and 1 in the center of the 2 buckets. I figured could put more power to the center one.