Nice system. Running a diffusion pump "blind" is not a good idea. Even if the pressure is safe, you can never determine if the system was evacuated enough to be clean for a good run. Ion gauges are cheap and readily available on ebay (assuming that is available - however, making one isn't very difficult if that is an issue.) Hope your DP oil is ok. Strange your micron range gauge wasn't warning you of the high (100 microns is very high for a fusor) pressure.
A side note: I see you have a water cooled cold trap that use's the DP water; be careful that doesn't take too much cooling capacity from the pump and allow the oil to get too hot. A trap isn't necessary at all for a fusor but I do think it is a nice feature. I don't see a gate valve between the DP and your chamber. Is that just not visible?
Not a fan of spark plugs for high voltage feed-thru's. Besides a a gate valve, a decent HV feed thru is a very useful addition to any future real fusor (besides deuterium and the required power supply ... .) Again, a HV feed thru is rather easy to construct so if cost is an issue (and I find those things rather expensive and made my own) that might be a better way to go then a spark plug.
I do not see your grounding wire (again, might be hidden or I missed it.) In any case, I use multiple ground points and wires to my fusor; a real fusor supply (which you may have no interest in) is terribly lethal and having redundant grounds is both smart and a critical safety feature - especial with a metal support structure. Using just a ground through the power supply isn't the safest way to go; a master ground wire to a know grounding source is far and away the best high voltage feature one can add to protect one's self.