I thought I was hearing some pinging under load above 2k rpm but wasn't sure. So I dialed back the vacuum advance and I think the limiter is as far as it goes, couldn't keep track of the ticks and didn't want to take it out to check. Maybe 10* vacuum advance now, or 8*? Had to reset initial timing when I moved the limiter cam, and it fell on 12* and seemed to work well there. Didn't touch the springs, one heavy and one medium still. Wow, big difference, very responsive to acceleration now. No stumbling on warm up. I sealed up the threads of the idle mixture screw with teflon tape too, which may also have removed a vacuum leak there.
Unfortunately will undo those settings when I get my replacement vacuum canister, but then I can drill a hole in it and put the limiter on the other end so I can adjust total vacuum advance without having to reset initial timing.
