The Anaconda as you have it scaled here should, by rights, have around 2,200 TC capacity. I have not run the numbers for the other ships, and assume that fuel needs, etc, scale linearly with volume.
Please note, the picture you see there shows the mk III at 33% rather than the 50% I have used (actually, the mk III is at 100% and the anaconda at 200% but proportionally it's the same).
So assuming your calculations based on my picture above are correct, we can readjust for a mk III as it appears in the game (c.f. mk III with python pic above).
0.33 x 0.33 x 0.33 = 0.036 (proportional volume at 33%)
0.5 x 0.5 x 0.5 = 0.125 (proportional volume at 50%)
If anaconda can house an estimated 2, 200 compared to a baseline mk III at 33%, then compared to one at 50%...
2,200 x 0.036 = 79.2 (anacondas proportional capacity in the standard game)
79.2 ÷ 0.125 = 633.6 (anacondas proportional capacity in this experimental build)
So (if my maths is correct), not quite the 750 capacity that we actually have but a darn sight closer than either the triple capacity of 2,200 you mention or the just over one tenth capacity of the standard game @ 79.2 .
If you want to scale the Thargon down without making it much harder to fight, you could either make it "Softer" so that it takes less energy to destroy, or weaken its firepower a bit. Possibly a bit of both. (Still harder to kill, but the need would not be quite as urgent. Much more mosquito than falcon, but still a threat when swarming)
Yes, I've mentioned similar with regards to the fighters upthread a couple of times. I prefer making them more fragile generally. In this build they are unchanged.
As for windows builds, I thought that's what I did?
Can only the devs access a pull request?