As these kits have re-appeared on eBay in May 2021, more questions have been posted online. I think the input current consumption is not documented, or at least confirmed. So here you go.
My one and only kit of these, with a 2BP1 CRT (spec'ed at 650 mA filament), draws less than 800 mA at 13 Vdc input.
The voltage across the neon bulb is 56 Vdc.
HTH
