I'd set the initial with the "vacuum gauge method" & yes you need more than 10 then shorten the slots to get 36 total then play with spring/combo staying just under the pinging point at WOT up thru the gears & you may need heavier springs. I'm thinking that ain't too wild of a cam & if not I'd solder the butterflies closed & concentrate my efforts on the dual carb system (not sure if you're on both idle circuits or not) & I'm not knowledgeable on dual carb setups. You would want the butterflies closed their normal amount or close to it I'd think. Make sure the floats ain't waterlogged & their level is correct & check fuel psi. Holler how it goes