I've been using MSD stuff since the late 70's and have yet to be disappointed.
Like Mr. P sez.......look around the track and see what is working for others.
My latest is a 6 AL 2 programmable and I haven't lit it up yet , but it has way more features than I have a use for.
I went this way over a regular 6 AL so I could map the ignition curve with a locked distributor , but this thing has enough limits and retards to do pretty much anything you would want to without going up to the top shelf of ignitions.