This topic applies to most of your mods.

Many of the items you I introduced (aluminum plates, the chemical stuff, etc) take the place of some vanilla item, and end up being slotted into the science ingredient list, which requires mass production of them.

But many of the alloys are used mainly for things like mall items (bronze, the numbered aluminum alloyed, etc), which means they're not really needed to be mass produced.
This feels very weird. I think finding a way to integrate all of them into the progression tree would improve the experience, since adding more resources that don't end up being used is sorta pointless.

Thanks for this feedback. Yeah it's a tough call at times. With the numbered alloys, I put one of them in science, but yeah the other one is not in science and therefore needs far less production, same with bronze.

I try to put almost everything into science, but keeping the vanilla feel makes it difficult.

I could probably try to squeeze these 2 alloys into some SE science, maybe even K2.

I may eventually do a mini rework of vanilla science to address it directly in vanilla as well, but that's very tentative and may not happen.

You could make a new mod that adds new science packs that use them. Or have tiered science packs like the SE packs, that use the new ingredients for them.

I will consider doing this after Noble Metals. No promises though, I haven't really put enough thought into it quite yet :)