Hi.
I just did the 883-1200 Viseco conversion and so far all is well.
What if I want to put in a set of cams and have the head ported later on, do I have to put in new cylinder base gaskets or do they live twice??

As long as you don't knock the cylinders loose, you're OK. But you'll get more HP per dollar if you port the 883 heads than you will by adding cams.