For what I understand, you would use a low comp. ratio because your forcing more air in. Upping the cylinder pressure like it has more compresion. So you don't start with a high compresion and add more.
A cm with a wider centerline (And it's timing of the events of the blower cam) help trap more of the charge of air and fuel. A narrower centerline cam, like typical 110 centerlines allow the air and fuel to escape since theres more overlap.
A low ratio for these engines I have seen recomended starting at 8.5-1 and lower. I don't know how high of a static ratio you can start with and then add pressure and/or how much pressure.
