Those are good questions that I don't think I can answer. I think the spooling is not going to be an issue, regardless. I have a lot of back pressure on that car. However, those are both far more a function of the turbo than the cam. Proper turbo sizing is hard, because companies don't release compressor AND turbine maps. So, we're left with trial and error as a community. We see what's worked for other people, and we pick what we think is best for us. But, turbo sizing properly can make a turbo spool wherever you want, make any power you want, and have less backpressure than boost. When you get close, all of these things become trade offs with each other. We all want a turbo that spools at 2500 rpm, makes 1000+ hp, and has 0 back pressure. But, I'll settle for a turbo that makes the power I'm shooting for, spools fast enough that it's not an issue, and doesn't have back pressure that limits the power or hurts the motor. I've accomplished all of those things with the GTS 76 in one car and the GT4202R (same compressor wheel, bigger turbine housing & wheel) in the other.
I think the cam can maybe make a couple hundred RPM difference, 2 digit power differences, and a WORLD of difference in driveability. My advice for a street car is let the turbo do the heavy lifting and get a nicely driveable cam. Beautiful thing about turbos is that you don't need a whole lot of cam. They actually do better without overlap. So power, torque, and streetability all come together in one.