I got a BK Precision PR 28A from Amazon.com to test the HV (it was 2700V) on my spectrum analyzer display. Goes to 40kV so they say. At $64 new it wasn't worth going to ebay for something used. They supply three tips, a point, a hook and metal plate which I assume is for slipping under CRT anode connectors.
It worked fine, but given the test point is a plated through hole, I had to use the pointed tip and hold the probe in place. Resting it on the chassis worked, but I had to watch out it didn't slip.
The scary part of this adventure was when I discharged the tube. The recommended method was to connect a lead from a long flat blade screwdriver to the chassis and slide it under the anode connection. So I got an alligator clip lead out - you know, the ones that you get half a dozen of for about $5 - and because I was paranoid, checked its resistance. Open circuit! I found at least two of the leads were open circuit - the copper breaks under the crimp.
Perhaps I'll buy some better quality ones or make my own...