well, i asked him yesterday, and, well, no more knowledge than before. he bought the cars/engines already done, and knew they were jetted for alcohol, but didn't know about particulars.
he used to run gas through at the end of the race weekend to help against corrosion from the methanol.
your small engine builder will probably help you best. you'll need to find one knowledgeable about running these on alcohol. the ones i'm talking of are running straight methonal.
if you wish to run only about 10%, your carb should probably have enough adjustment in it for that.
otherwise, your carb will have to be re-jetted for 100%.