[fields 100]

As the new cheap testers can not check capacitors for leakage at high B+, do those vintage ones with a "magic eye" do that job?

[Mondial]

Yes, the testers with the eye tubes check leakage at high voltage. I have a Heathkit one ( an IT-11) which applies up to 600 VDC to check for leakage. It also comes in handy for reforming electrolytics which have been sitting idle for a long time. 

The IT-11 I have comes up regularly on ebay, selling for $30- $40.