My Carb calls for me to run 18-20* initial timing but if I go over 16* with 10* vacuum advance hooked up it will detonate under part throttle load. So would running 20* initial with only 6* vacuum advance have any performance gain at idle and part throttle. if both combinations are going to give me 26*. I know the 20* will be better on the wide open but I am looking for better off idle and responsiveness from my carb. (which is alittle too big), Thanks David

Have you tried running less initial and using full manifold vacuum for your vacuum advance? Of course you'll hve to readjust your curve to get 32-36 total (without the vacuum).