HELP? pistion & crank balance

[DCNZ]

An RG125 std piston weigh's aproxamitly 220 gram's, an RG150 std piston weigh's aproxamitly 235 gram's & a 150 +0.25o/s pistion weighs aproxamitly 240 gram's so how is an RG150, that was balanced to 235 gram's, going to react when another 5 grams are added and how would an RG125 react with an extra 20 grams added?
Is it possable to drill the crank in order to balance the pistion weight and if so how much and where would I remove the meterial to get an equil balance. Is there a knowen place and formula for this.
I ony ask becouse I am trying to put two RG150 top end's onto an RGV250. I have figured out every aspect other than how to balance it. One Rg150 top end has a std pistion, the other has a +0.25o/s pistion. Has this ever been done before? Do you know how I could get in contact with some one that wouldn't mind giving me some advise?
Thank's for any imput.

[DCNZ]

Im already a member of RGV250.co.uk

[ajturbo]

just do it and tell us what happens...