I installed true nukes part way through the playthrough and decided I'd slowly grow my mega factory while one tritium reactor runs with breeder cells, at 720hours I can finally detonate the Gt, but that is not the end, and I plan on building a newer better factory with crater as the center piece.
There is still the issue of detonating the 1Gt, as I've made several attempts so far and my first one it took ~4hours to process 1 frame before the game finally crashed at around 9-10hours in. I did disable the fires and halted all production in the factory in hopes that it will have some sort of miniscule improvement on processing time, but as far as I understand reducing the blast wave radius is the only real way to make it faster.
I asked things here a few times, but thanks for the awesome and very satisfying mod, I'll definitely keep it in my loadout for future mega factories.

Thanks!
Yeah, the 1Gt is very big, and has a huge performance impact - notably it scales with the amount of (nearby) map loaded, so works fine on small maps or a long way from spawn, but struggles when in the middle of a large area. I'm not really sure there's that much I can do, though I'll always be on the lookout for improvements.

Setting the effect range reduction to 8 (which I believe is 1/8th the size) was just enough to put my millions of solar panels and other entites out of range, and at that point it detonated within 20min, now I gotta try and cleanup all the stone around the crater.
I don't really know how mods for this game work optimization wise, but it definitely seems like it's as good as it can be for the scale of what you're trying to do with it.

I didn't want to make yet another post if not necessary, but if you happen to see this I am getting a constant 3.5-4ms caused by true nukes, none have been detonated in at least 10 hours. The only thing I'm doing related to the mod is I'm moving throughout the 1gt crater generating the chunks it blew up and removing mounds. I didn't see any debug commands other than to force all water to be filled instantly.
However I did notice it hovering around that before I even detonated it, any ideas ?

The mod simulates the blast going through a chunk when it's loaded, so if you're loading chunks, then the mod will be running.
There isn't a clean way around this, but it should drop off as you stop loading chunks, and the performance cost will reduce as you get further away.