I wear Tech 10's size 11. Had the same prob so i raised the shifter about a 1/4" and dropped the brake the same and the fit is much better now. I also changed out the peg's to IMS XR pegs they are a bit wider and longer. Oh and 7/8" handlebar risers.
Found all this info here at the KLX250 forum using the search function.

WD

 

i have thor quadrants, size 14. I bent mine to hell.... need a new one. looking for a better than stock one, but i think im screwed.

 

I spoke to Moose Racing directly and they told me they had no plans to make a shifter for the KLX250S. We are shi! out of luck when it comes to a lot of aftermarket products for this bike. Too bad, many compnaies are missing out on sales they could be making to all the owners of this awsome "Green" machine!

 

Ok here's my question: How many different splines could there be out there I mean come on. There should be dozens of shifters that should fit.

 

it's not the splines as mush as the bend of the lever. once i need one i'll just get one that's sorta close and just "manipulate" a bit.

 

Yeah, I think that's the ticket. Find one with a similar bend and tweak on it.

 

maybe ill stop at the dealer and see whats close...

 

Yeah, I'll try to remember to do the same.