nice job no the engine... wanted to do the same with mine, but was impatient and wanted to get her finished so left the heads on....
Hope you'll be giving it a lick of paint whilst its out...
re: valve clearances, not sure on the 600's, but i'd assume it would be similar to the 9's - having just done my clearances, the exhaust valves factory spec are between 0 and 0.05mm so yours may be ok...? double check factory spec though, but speaking from experience with the 900, so long as you can spin the cam with no binding when the opening arm is off to the side, you should be fine.
oh and if you do end up replacing shims - hide the swear jar
