That's an interesting idea. Black science suffers from this in the base game too. It's only needed for a handful of technologies so you can get away with a tiny factory with big stock piles.
I am a very slow factorio player, partly because I keep modding it, so I'm only now getting to white science. I'm honestly a bit disappointed in it. It's basically free and I have a surplus with only two assemblers. So it's more like red science. I haven't gotten to the planet sciences yet but I'm sad to hear that it's basically the same tier as green or blue science.
I created this mod to help balance mixing lots of big mods like Space Exploration with other tiny mods like Aircraft (or my own mods). All of those mods followed a mostly linear progression in tech costs so my simple depth-based approach worked well. I am going to try and think of some other balancing algorithms to try.
What do you think about changing the science recipes for the late game techs to be more expensive? That has a similar effect, albeit a lot more annoying to balance.
What do you think about a mod option that lets you set the tech-tier for any tech beaker? It would override the ones I calculate. So you could set space science to being tier 1 and then the rest would rebalance accordingly. That would give costs like:
16r/8g/4b/2p/2y/16space/8vulcanus/8gleba/1promethium
The tier calculation tries to ignore missing science packs in the cost to support mods like Krastorio, where the old science packs become totally obsolete. So even if you hard-code something to like tier 100, it would still treat it like it was n+1.