Varying spark, out of ideas

Well, I scavenged the vacuum canister from the new one and put on the old one back on, setting the point gap again first, and she's running about as good as I've ever seen her. Ignition timing stays pretty steady. I guess I can call the new distributor a dud.
I started to run a compression test again and was getting similar numbers. I am hoping it's because it's a cheap gauge and/or user error. The engine still has a hesitation issue that's remained throughout quite a lot of work, too, but I'll take it.