I like to disable the big spring completely by bending the tab for it in so it never comes actually works. Most of the stock distributors have the last bit of timing come in very slowly at high rpms, most likely because 1970's fuel was so sub par. If the little spring is OK, adjust it so the curve starts at 1000 crank rpm's and it should be all in before 3500 hopefully and have a stabile idle. With mild cams like K, D, VV-61 & VV-71, you can pick up a bit of torque around 2000-3000rpm, but if it pings in this range tighten the spring slightly in stages. After 3000rpm you want no pinging because this is starting to get close to peak BMEP & torque, and pinging here can rapidly become detonation and then tears with your compression ring in multiple pieces.