Converting spark gap tesla coil to a VCCT

There is my old spark gap tesla coil project. Video is rushed and badly made but you should see the parts. Since results were not satisfying and I got a vacuum tube for cheap I want to convert it to a VCCT. There is the link of the post about the vacuum tube: https://www.electro-tech-online.com/posts/1382586/. BTW my other post about my first tesla coil can be found on page 2 of the high voltage forum page, there must be very low posts about high voltage since its still on the page 2 after a year :/
Anyway I want to use this schematic: https://www.stevehv.4hv.org/VTTC5/833Aschematic.JPG
Instead of using a single MOT and a voltage multiplier I want to use 2 MOT's in series to double the voltage without losing current, my vacuum tube should handle that since max anode voltage is 6kv and max anode current is 1.5 amps in datasheet. Surely there must be other chages in the circuit in order to make this work.
I am going to use the existing modified MOT in order to feed the filament voltage. I might not need to rewind it since in the past I put lots of center tabs on it for future uses. I can use AC to supply filament voltage but probably my MOT is wound to have 12 volts when converted to DC so can someone inform me about using DC on filament is a problem or not. And can someone tell me the changes I need to make on the schematic for making it compatible with my setup in mind. Thanks

When I see other VCCT builds I noticed people using a voltage multiplier on two microwave oven transformers in parallel instead using them in series. Is it for limiting current or is there a other benefit of it. Because If there isnt then It looks like its wasting energy on diodes.