That's actually a pretty good understanding you have. I would highly suggest getting a program to help you out. I got WinISD and it is 99% accurate
to my current build so I am very pleased with it. There are many others, but this one was at least free.
The program will show you what happens when you mess with those ratios you are talking about. It can't hurt you to change them, it will only change the outcome.
and a general rule of thumb, make sure your subs have a Qts. greater than .5