You have to establish your own comfort zone. It would be nice to be able to measure this stuff as mentioned but radmeters still haven't made it into collectors hands in any great numbers. I'm thinking the threat of luminous dials may be quite small but having said that, I sold an old RCAF hand portable compass (P106??) with filled glass vials on the card and I couldn't get it out of the house quickly enough. I tend to be overly cautious about that type of thing though.
If I had a dial that had been repainted with Super-LumiNova, I would not consider that a degradation of the article in the least bit. I'm in a watch and clock collectors club and doing that is simply a matter of course for many watch collectors. Mind you some of those guys have 1,000+ pocket watches or more and I suppose the rads would add up a bit.
Incidentally, we used to have a two pint can of the paint in the weapons section at Wainwright for painting aiming lines on the 2" mortar tubes. I have no idea if that stuff was nasty or not, but it just sat round like any can of paint. Hmm, maybe that's why I ended up with Lymphoma!