Peter you are right with signal to noise ratio, general rule of thumb is tertiary number of subs 3,6,9.
The issue though peter is that 30 seconds you wont capture enough signal and this is where the 1 10 min sub will smash 300 30 second subs six ways to china as the signal will be strong enough to push past the "noise". Is it going to be a show stopper? No. will it have far more image yes! whats the use of having a smooth picture of black and a couple of white spots.?
