I weight match all the moving parts to 1/10 gram tolerance or closer (A dollar bill weighs one gram) but in my experience, inline six crankshafts just aren't worth the trouble, especially stovebolts. The cylinder head won't let one turn fast enough to get into dangerous RPM territory. Now a Datsun 280Z or maybe a Toyota Supra with a twin cam cross flow head and a 7K+ RPM redline might be a different kettle of fish!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!