This is for the VL isn't it? Not your 33...
.8mm is chopping a fair bit out of a 25 head... I'll be interested in what Matt/insert chosen machinist has to say about it. You'll have to watch your valve clearance too. That head looked pretty fkn cooked though!
I have some slightly used wiseco rb25/30 pistons/pins/locks without rings going cheap if you wan't some :-)
If it's just a slapper, the sparkplug tip damaged piston will be okish, just smooth the divits out a little, also check the bore very carefully.
I have some 25/30 bits and bobs kicking about. I'll have a look, see what I can find.
The conversion is easy. There are a couple of things that arn't covered in the guide, sing out if you need a hand.
J.