It is important to supress corona as all costs. This means rounded connections or connections covered with HV silicone putty. Ozone will ionize in a closed box and conduct like crazy. 10KV is not much High voltage (unless you are touching it). I would think that with little corona and no circulating air 1.25" would be fine to the nearest ground. with plastic baffles that could be nearly zero separation. with good air flow and exhausting to outside 1" separation might be OK.
I would probably use baffles if some of my compoents with the full 10kv differential were forced to be closer than 3/4".
I doubt if any of your components other than limiting resistors will get even warm. Be also aware that meter dropping resistors for voltage readings can warm a bit especially is you can't find the appropriate wattage.
example: A 1 ma meter movement reading 10kv would need a 10 meg 10 watt resistor!! I don't think they are available, but could be made up from banks of other resistors. I prefer 100ua meters. These would only require a 100 meg 1 watt resistor. ( a much more avaialble solution).
Make absolutely sure that one leg of all meters are effectively at gound potential!!!!!!!!!!!!
The ammeter is absolutely in the ground line. For a fusor, the voltmeter's positive terminal should be there too. Otherwise, you can be killed or badly shocked pointing to or touching the meter face with your finger!!! Never float a meter that you can touch with a finger or bump against. If a meter must be floated, encase it in plastic fully with a 1" separation from the face and the plastic viewport.
Richard Hull
Created on Monday, April 23, 2001 9:51 AM EDT by Richard Hull