I typically re-string a wheel like yours with new spokes. Unless I'm going for historical accuracy, or it isn't going to get ridden too much, nobody cares that the vintage wheel has DT competition spokes, and they especially like how much more reliable it is. I can just replace one spoke at a time watching TV since I don't have to focus on a lacing pattern. It clearly adds cost, but I think modern spokes have much better quality control and it sure makes truing go faster. If you can't get a wheel trued after spoke replacement, then you have a particularly bad rim.
When truing, I've learned the hard way to not even think about lateral truing until I get radial perfect. This is where too much focus on even tension can really slow you down. Once you get sufficient tension on spokes and are perfectly radially true, then lateral is quite simple. But I usually won't have even tension when dealing with a vintage rim.