Ok I'm in the process of purchasing some wheels. Need Help with offset. I send hrs on here but want a broad opinion.

I'm trying to do 20x10 square set up. Fender rolled already and drop to the point of no wheel gap.

I'm being ask about "how deep is base on your brake caliper" and all that of course I don't know. Basically there recommending 20x9.5 ET38. But I feel for concaves thats hella weak. What is the BEST OFFSET or deep I can go with 20x10. front and back chamber kit will be install.