Opinion on my compression ratio for PD boost

A little more information is necessary to figure out what compression ratio you have. What kind of heads do you have? If they are ported, what is your chamber volume? You said you have 18cc dish pistons, but do you have valve reliefs cut into them? With these questions answered, I should be able to get you a rough idea of your CR. FYI, determining an optimum CR depends on how much boost and timing you want to run (so please include this figures as well).

If you would really like to get specific, i.e. power goals or et time/trap speed, answer these questions.

What is the flow data on your heads?
What cam profile are you using?
what intake manifold do you have?
What exhaust setup are you using?
What is the ring gap on your .020 over-bore is?

If you would like some recommendations, don't hesitate to ask. I would be happy to help. Maybe it will be less expensive for you than it has been for me. If nothing else, I can tell you what didn't work for me.

Hope I can help.

One of the difference between a thicker head gasket and more dish in the piston is the amount of piston to head clearance or squish. You normally want to run more clearance in a boosted motor than a N/A motor, but this does depend on the amount of boost.