[Arran]

The Solar Sealtite ones, at least the ones encased in molded wax from the 1940s, seem to hold up better then most other makes from that era. Sprague paper caps are another that seem to hold up better then others, but given the age of all of these you can't trust them if there is a high voltage potential across them. Canadian Westinghouse was run a bit differently then the U.S company, they actually built most of their own sets, though likely under license. The Columnaire they built in Canada was called a model 801, and they used a similar circuit to an RCA R7 Nipperette, but was mechanically different in both the clock model, and the more conventional models, the biggest difference was that they had the tuning condenser mounted on top of the chassis across the front. In those sets they didn't use as many tubular paper capacitors, and where they did they didn't have the rolled over ends. The filter caps were so called "Dry electrolytics" mounted in a square metal box on top of the chassis. I think the oldest RCA and G.E sets I saw with the caps with the rolled over ends was maybe 1936, and they were using them right up until the war, as I mentioned they are fairly easy to get the innards out of and restuff, no heat gun or toaster oven needed. 
Regards
Arran