i would do forged flat-tops and adjust the compression with the chamber size on the heads.
I ran flat tops for years with aluminum 58cc mag heads, but had to run premium fuel.
Stock heads normally cc out around 74cc so dropping compression is easy.
I have flat tops in the Duster and I'm using the same heads I had on the Duster and even that I had to use premium with a tickle of race gas...
I want to be able to use straight junk gas and not think twice...