Plug chop during break-in?

[Greaser Greg]

Swapped an R5 top end from first over with stage .5 balance porting jugs and stock pistons with trimmed skirts, to second over wossners and stock cylinders. The cylinders and pistons had been run about ten miles maybe, (just going on p.o. statement and trip odometer) still very obviously cross-hatched and most of the color still on pistons. My question is: do I run it for 50 or so miles to seat the rings before going past 6k for a plug reading? Or, what? Pulls good up to six, but slogs out after that. Plugs looked dark around the edges, but caramel tips and electrode with one white spot on tip on right cylinder, the one that seized before.

[SUPERTUNE]

Run it hard at wide open throttle, short shift, but very brief and 2000 rpm under redline for break-in. 150 miles should be plenty for break-in with a few heat cycles, then start with your plug chops for reading new plugs with less than 10 miles on them...
chuck