I am about to blather my opinion at you, so take it for what it's worth:
I think jacket BCDs are not that great really in any fashion, and I say that as a scuba instructor. They are built for comfort, but not for speed as the saying goes. If you want one BCD that can do everything, then build a backplate and wing (BPW) with one of the VDH backplates:
http://vintagedoublehose.com/store/#!/V ... ry=1874499
With a good BPW, you can dive double hose, single tanks, and doubles. Really, by swapping a wing or a plate, you can dive anything that you could possibly ever want to dive. Outside of BCDs approved for Navy use (Zeagle Ranger, etc), there are not many conventional BCDs that can do that. There is a wealth of information on this site pertaining to just that in the modern double hose diving section. You will probably read about BPW double hose diving there until your legs fall asleep in your chair.
Also, this is totally doable as a college student. Years ago, when I was living off of my GI Bill and in grad school, I was still scraping together ways to dive double hose. Just keep in mind that, like climbing, hiking, shooting sports, and many other things, you have to know where you can go cheap and where you cannot. There is also plenty of advice on that here on the forum as well. Don't buy something cheap and rotten on Ebay without doing some basic intelligence gathering about said gear. Just because it was made in the 60s doesn't mean it was good.
The impossible missions are the only ones which succeed. -JYC