Arias state a 4 thou clearance is required and recently i think they've changed it to 4.5 thou.
With the rings , we found the stock arias chrome rings to be a bit iffy with some engines getting quite a bit of blow-by. I used nissan n1 rings in my arias pistons but its not running yet so i can't comment. Was gonna run the engine in on penrite HPR 15 as some people i know have done it with good results. Will post up results in the coming weeks.