Mr Pete....too late, those pistons are already installed and running on this bike. That did cross my mind but my thinking was that I'd probably botch it somehow.
I'll most likely do it on this new build.
drainsurgeion....I started with a little 120 grit flap sander for the dremel tool. Being very careful of the valve seats. 200, 320, 500, 800, 1200 wet sand and if I remember right 2000 wet sand, then steel wool and WD40. Then broke out the jewelers rouge. Like I said I had a lot of time on my hands.
I even smoothed out and polished the exhaust ports and matched up the manifold to the head so there is not any lip where they meet.