It is possible to use, but it requires some imagination.
I use a B&K 707. Get a octal to UX4 socket adapter, use socket 33, or the one used for octal rectifiers. TEST 2 will test the anode output. Set the filament voltage to whatever your tube is, erring in the lower range i.e. 1 for 1.5 filament voltage or 6 for 6.3 etc, and put the sensitivity at 0. Use a known good tube and set sensitivity so that test 2 registers 120 then record the values as a standard for that tube. You can then test and match any other UX4 tube or tube set of that kind.
RZ3 rectifiers can just be tested with the UX4 adapter as if they are 5u4.
I use a B&K 707. Get a octal to UX4 socket adapter, use socket 33, or the one used for octal rectifiers. TEST 2 will test the anode output. Set the filament voltage to whatever your tube is, erring in the lower range i.e. 1 for 1.5 filament voltage or 6 for 6.3 etc, and put the sensitivity at 0. Use a known good tube and set sensitivity so that test 2 registers 120 then record the values as a standard for that tube. You can then test and match any other UX4 tube or tube set of that kind.
RZ3 rectifiers can just be tested with the UX4 adapter as if they are 5u4.