L1=L2 :

739pF    0.34 mH    0.5 Ohm

made from 12.5 meter 1.5mm2 speaker wire. oxygen free pure copper.
24cm total diameter
5.8cm inner hole diameter.
9.1 cm coil width.

inner diameter made by 13cm free end (for series connecting windings), then 18.2cm into a circle, as the 5.8cm inner hole.

10cm of 1.5mm2 speaker wire (2 wires)
has a copper mass of 2.62 gram

so a 12.5m coil has a copper mass of 327.5 gram

10cm of 2,5mm2 speaker wires (2 wires)
has a copper mass of 4,55gr
3.27.5 : 4.55= 71.978

So a 7,198 meter 2,5mm2 coil has equal copper mass as a 12,5m 1,5mm2 coil

2.5mm2
7.198 meter speakerwire.

capacitance= 332pF
inductance=0.13mH
resistance=0.2 Ohm
total diameter=29.6 cm [12-12-19 correction:19.6cm -10 from measure tape]
inner hole diameter=2.1cm

I'm going to make a new 2.5mm2 bifilar coil.
This time I will separate the windings.
This coil will be used as an L1 coil.

The goal, is to still magnetically couple the windings (mutual inductance), but distance them enough, to reduce the capacitance. This will raise the resonant frequency of the coil, which then makes a much faster impulse possible (shorter duration).

As the back emf impulse, also creates a very temporary dielectric field in L1, it will create longitudinal pressure.
The distance between the windings, will make the volume of Aether bigger. Which hopefully will create more inertia effects.

2.5mm2
(2x) 7.198 meter speaker wire.
5.8cm inner hole diameter

I first separated the 2 wires of the speakerwire.
then rolled them stacked together, on a rol of tape.

hot glued both (outsides) of the coil.

then separate the 2 windings, and glue the other sides.

this way the windimgs will still be equal im size and windings. I could also glue them with a dielectric together like silicone.
But I have to thing about this.

First I want to measure at what distance the inductance is being coupled.
I will do this with nylon rings im between the windings, and measure the inductance at several distances.

I could also measure capacity, but this would be changing if I add a dielectric. I intend to use silicone as a glue (with nylon rings for spacing)

I made the new L1 windings, and made several measurements, while having them at variable distances (by using nylon rings).

Rings      distance    inductance   capacitance
stacked    in mm         mH               pF
0               pvc            0,12            232 
1               2.5            0,12            107
2               5               0,11             62
3               7.4            0,11             51
4               9.8            0,11             41
5              12.3           0,10             35

As expected, the inductance barely shanges, but the capacitance quickly drops. I guess I need a distance of maximal 2 rings, as I still need some dielectric coupling. The silicone will increase it some more.
Since I am limited to 1200V impulses by the SiC mosfets, will use 2 rings, 5mm distance between the windings. filled with silicone.

smells terrible :(
will do measurements of inductance and capacitance when the smell disappears

the new L1 is 5mm distanced by white silicone kit, and nylon rings(to keep equal distance). both pretty good dielectrics.
Before, with only the nylon rings, I measured:
0,11mH inductance and (only) 62 pF capacitance. (and 0,3 Ohm)

Now with  the white silicone kit:
0.12mH inductance, and 134pF (and 0.2 Ohm)

The original L1 coil, that produced 500nS impulses had 232pF of capacitance and 0.12mH inductance.

The reduced capacitance in the new coil, will raise the resonant frequency of the L1 coil, at which the impulse will be.

Very happy I chose 2 nylon rings instead of just one (would have increased capacitance)

did quick test: -1100V impulse 450nS at 61kHz good enough for now

1200v double setup uses this now, but I intend to use high voltage igbt's in the future:
Mosfet gate driver:
1EDI60I12AF
https://www.infineon.com/dgdl/Infineon-1EDIXXI12AF-DS-v02_00-EN.pdf?fileId=db3a3043427ac3e201428e648a333734

for this SiC mosfet:
2m0160120d
https://www.infineon.com/dgdl/Infineon-1EDIXXI12AF-DS-v02_00-EN.pdf?fileId=db3a3043427ac3e201428e648a333734

gate source voltage recomended, 20V, this is set by my boost buck converter
https://www.mouser.com/datasheet/2/90/2m0160120d-838563.pdf

L1=L2 = 10meter 2.5mm2 speakerwire= 455gram copper

1,5mm2 10cm=2.62gram
2.5mm2 10cm=4.55gram
10cm of 0.75mm2 = 1.285gr

455/26.2=17.300 meter of 1,5mm2 speaker wire needed for L3.
then L3 is equal copper mass to L2 (455gram).

edit:
10cm of 4mm2 speaker wire(2)=6.915 gram.

10 meter 2,5mm2= 455 gram /69.15=6.580 meter for L3 if 4mm2 is used (equal copper mass)