having know 1200rc for years through this site, the set up was originally off an a12 with blowthrough if my old brain can remember, but not much exisits off that original set up anymore.

The problem is the injectors running out of flow and leaning out from history, and if your still using the welded cor for the cooler, that always had some flow issues.

A decompressed a series will hold but not reliably with upwards of 10psi for a daily driver.
I like the twin set up, it has its merrits and potential. The boost needs contoling but with that said theoretically tow turbos from a 1 litre are well matched to the engine in a parralel set up, at least its not sequential (staged set yps like rx7) set upwhich have more problems.

My only advise is like ANGE, keep with it 1200rc, but build one motor this time and do it right! maybe an a12 with a15 head etc... long stroke large bore engines like a15 historically dont like high compressions, but small stroke large bore ones do..

maybe a a12 with 76mm bore for the a15 head and thick head gasket might be a goer...