L12 Mod on KX18D Pro II with M2600+ - will it make a difference?

I have a M2600+ on the KX18D Pro II MOBO.

I have a couple of issues that I am having problems resolving.

1) Cant use 10 or 10.5 multipliers over 200FSB (won't even boot)

2) Can't get my FSB above 232 at 11X, 224 at 11.5X and 207 at 12X (Vdimm modded)

Will the L12 mod be of benefit in increasing the FSB?
As this chip is the Barton core, will I have to do the L12 mod from 133 to 166 to 200 or just the 166 to 200?

Can a BIOS mod be made to use a multiplier at say 11.25 instead of 11 or 11.5? (Why arn't quarter increases available)?

Thanks.....

I can boot 238fsb with my value ram after the L12 mod. Works well for the KX18D.