Better design?

Jar capacitor with 5000v xmfr

Picture of Better design?
Better design of what exactly?

Do you mean the TC in general because you can make numerous changes.
The coil it's self it's hard to find high voltage parts in this town you pretty much have to make them in gonna send supplies to a shop to coil a bigger one
Well that copper primary you've made should have more turns, it will need it seeing as you're using bottle capacitors. And you're secondary coil needs to be wound out of single strand enameled copper wire, you can get the wire out of a TV or a oven fan.