Using two stock light springs in distributor advance, good idea?

Well, I guess best case scenario is to use a distributor machine if you can get access to one. Your baseline based on your combination is still a "guess" being that you are going to get "close" as far as how much static, and how much mechanical all in by what rpm. You are still going to have to fine tune in what is "optimal to your combination" with some seat of the pants, chassis dyno, or preferably, drag strip tuning.