360 compression issues. pick a piston??

If you really, really, want the most bang for the buck, then pick the cam first, and don't change your mind. Then set the Dcr(Dynamic compression ratio) to run it on your local Premium, and at your altitude.
If you pick a compression ratio to deal with bad gas, you will not get the best bang for the buck. The way to deal with bad gas is either run it out at part throttle, when the chambers only require a much lower octane gas, or drain it out, and burn it in your lawn n garden equipment.Bad gas is not a big deal.
The intake closing angle, and the Dcr, and the gas,and the altitude,are just about married, if you want the most bang for the buck. Until you pick a cam, Scr means very little.It's easily possible to run 11.5 Scr on 91E10 with aluminum heads and the right cam. Running that same cam on 9.8 Scr would make it a big disappointment at lower rpms, and you would be band-aiding it with race gears and hi-stall TCs, and it would be no where near the best bang for the buck.
On the street with a lot of stop n go driving and lots of cruising, a conservative cam will be the most fun. But there's a tremendous difference among cam suppliers who provide similar ICAs but their cams will perform quite differently. This usually boils down to the ramps. Again, for most bang for the buck, you will want a cam with the highest lift and the most .050 duration, that still has the ICA you choose. This means either very careful shopping or a custom cam.
What I'm saying is this; you can easily find several cams from different cam-companies, that all sport the same or similar .050 intake duration numbers.And they might even have similar lifts. In this case they will all make similar power. But, and heres the key, they might all have very different ICAs. A late ICA will put a nice lope in the idle, which is what some guys want. A very early ICA will trap more charge and make low-rpm torque, which another guy might like. But the ICAs could be 5 to 10 degrees apart. If your engine is not set up for an early ICA, it might ping. If it's not set up for the late ICA, it might be soft off the line. Those 5 to 10 degrees could spell the difference of over 1 full point of Dcr! That is from say;8.0Dcr to 9.0Dcr.And that might correspond to close to 2 full points of Scr.Say 9.5 to 11.5.
This Dcr thing is way more important than a lot of guys suspect, and especially so for guys who want the MOST bang for the buck.
So pick the cam to fill your operating range, and get the fastest rate of lift and the highest lift, that the cam guy will sell you.And the springs that are matched to it. Get the ICA from the card. Plug it into the Dcr calculator, to spit out the Scr. Then go build it.
Another option might be to call MRL. Since his shop is spitting out engines with really nice numbers, he must know a thing or two about picking cams.
Or I can just tell you what works for me.......................your results may vary.