So I shouldn't make Naquadria obtainable? Okay. That means my fictitious element list is just Naquadah, Neutronium, and Magic (Any suggestions for a better name for that?). Any thoughts on how they'd be obtainable with fusion reactors? As in should they be obtainable? Because currently I've got Naquadah being obtainable with a number of 126 and Neutronium being obtainable as the fusion of two Naqudah but Magic has a high enough atomic numbers it isn't, I've strongly considered making Naquadah unobtainable through fusion but people who are actually experienced on end-game GT will probably know better, I can remove the ability to get neutronium as well if you want it to be unobtainable still. I've also considered adding a bunch of effects to magic to go with the fact you've got a vial of pure magic, I'll probably end up doing it. I have to investigate super high elements some more though as I've managed to crash the server and the client at the same time currently by playing with them, suspect a possible bug in MineChem related to the fission reactor when there is nothing half it's size.
For conversion rates the biggest one is that 1000L of a fluid is worth 1 dust in GT but dusts are worth 16 atoms and 1000mB of a fluid is worth 8, that's a major issue though if compatibility is wanted, otherwise I can just treat GT fluid as worth twice as much as minechem fluid. Other stuff like the fact that water buckets decompose to twice as much water as it needs to make them, although I think this is just due to your change.
Also can I change charcoal to only need 4 carbon or coal to need 16? Because it's needed to make carbon dust somewhat balanced, it won't really be due to the masses of carbon that are easily obtainable from cellulose but at least a little effort would be good.
Thoughts on things like ruby, emerald, or diamond dust. Should I make them decomposable and synthesisable? Note this is particularly important for ruby as a component of redstone.
Also what's with the weirder new nether star recipe? I could make that includes magic as well if you wanted, it's only obtainable from magical items which is basically just thaumcraft stuff.
What should I do on the materials added by other mods that I could make obtainable? Like most of the twilight forest materials and a lot of the metallurgy ones have simple components according to gregtech that I could very easily make it possible to get them, you'd need a synthesiser and a bunch of magical components to get the magic needed for those examples but it would be perfectly possible to make a lot more materials available. Osmiridium I was just planning on adding as a osmium iridium hybrid for example in the vein of Naquadah alloy where it's 1 osmium + 1 iridium = 1 osmiridium.
As far as molecules go I'll be at least adding the ones GT states exist in it's formulas, I'll avoid adding any but some may need to be added.
For synthesis for ones with weird formulas it's an issue, I'm just going with mass synthesis from the looks of things, so you can only synthesise redstone in lots of 25 for example.
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Apparently I forgot to post this earlier, oh well.
Quick mention on the most recent two posts, Naquadria and Enriched Naquadah are isotopes of Naquadah so unobtainable unless it's wanted for me to add them. Both Naquadah and Neutronium are not radioactive as well as being super late game materials which was why I made Neutronium only obtainable from Naquadah and considered Naquadah being unobtainable from fusion. I'm also going to be going through and any material that from other mods isn't usable in a pickaxe per the ftb page isn't getting in as they're useless, someone might want astral silver tools or something though so they're staying. I'm also keeping Ma as a super element, currently it's number 777 and I'm doing so to try and keep it requiring magical sources to obtain, as is it's a way of creating stuff like shards or thaumium from magical substances and the only way of getting things like mithril or midasium. Not including anything for firestone or firestone dust is fine, if anyone who knows more about later game gregtech chimes in I could do meteroic iron containing trace amounts of titanium just fine.