Re: Which probe is better suited for 2465B?
For probing 50 ohm signals it's best to use a simple passive low resistance probe. This also works well for fast logic signals. This will outperform all standard probes. Links to a couple of designs here: https://www.eevblog.com/forum/projects/lo-z-probe/
It's just a resistor, a length of 50 ohm co-ax and terminate your scope with 50 ohms. On a 2465B there's a switch for this. On lesser instruments you'll need a T and termination.
For high voltage you need a probe that is rated for that voltage.The P4100 looks suitable. Just take care around high voltages. If the high voltage comes from a low impedance source, such as a transformer direct from mains/line then it can kill you. I survived the experience but it hurt. A lot.