We must remember what caps are really for: protecting your power supply, i.e; Alternator and batteries. (okay and making sure that sub amp gets it's power) I feel it well worth it to cap my power supply then just run without it. In real life we should only worry about that sub amp, because it's the one that is going to have short term high amp draw, this is what causes havoc on power supply systems. Your tower system probably doesn't need to be capped, but caps are not that expensive compared to a couple of batteries and a new alternator. I don't know what kind of power you are running, but you can get a good hybrid cap from 5 to 25 farad and hook all your amps to it. Then you don't have to worry about anything. I have a 5 farad hybrid cap for 3000watts, a little overkill. I won't be replacing batteries or alternators anytime soon though. The questions of size isn't that much of an issue, becasue these hybrids are smaller than your convential rolling pin style. They are about half the size. 7 1/2” L x 5 1/8” W x 2 7/8” H
http://www.stingerelectronics.com/web/prods/capacitors.asp