I played this bass and my 8 string at rehearsal last night, it's always balanced effortlessly regardless of modifications, the strap pins are in the stock positions - centered in the end and the middle of the heel. Balance is an open question tho, as Clint (Stiles72) has shown, a players individual preference on strap length is likely going to change how the bass balances. He wears his basses a bit lower and favors a different right hand position than I do - I keep the strap a bit shorter and seem to have a bit of my lower rigt forearm on the upper bout while playing pickstyle. The Nikki Sixx Mk.II is no different than any other post '88 'Bird in terms of balance, tonewise, that's another story