I really like the idea of the stripe variants of the belts, but in practice I find it very hard to tell which direction the belts I am building are facing with it active, especially with very high tier belts. Perhaps some option to enable arrows as well would help? Maybe the side stripe + the arrows? Also, if possible, perhaps the thick stripe and also a black mask of the arrows on top of it (to "cut" them back out of the stripe)? For the thin arrows, I'm not sure if it would work better with the colored arrows or the black arrows. I suppose either might work? I don't know if combining multiple masks is very viable for the mod code. I see in an earlier thread you turned down coloring the whole belt, since it would need new masks, but perhaps at least some of these suggestions could be done without needing that?

Interesting idea. I honestly didn't think about combining more than one mask layer. I'm afraid it might tank performance, but I'll test it and see.
Combining masks in photoshop could be doable too (in comparison, the inverted arrows would be tougher to do with either techniques).
I'll run some tests later, rn I'm focusing on another mod I'm contributing to.

As for telling the direction of the belt while building, I'd like to add an overlay arrow pointing in the belt's direction whenever the cursor is hovering it. It's just hard to tell for some belts even with regular arrows.
I'm still looking for a proper solution to code it in though...