Could you do that if bob mods are installed, the slowest of your belt requires highest of bob instead of vanilla blue belt ? (This for the belt, the splitter, and underground belt).
It would also be nice to have same requirement for research, highest bob should be a requirement to research first ultimate belt. Thanks !

Second this, does not really make sense that you can start making a belt that is considerably better than the highest bob tier before you can even make the 4th belt tier. makes it feel really unbalanced.

First off, I do agree that it doesn't really make sense. Bob's belts are slower, and require higher tier tech and more expensive materials than my belts.

The primary reason I haven't done this is because I feel Bobs belts are worthless. They are way too expensive for what you get. By the time bobs belts are craft-able, the meager 33% and 66% faster speed when compared to express belts isn't all that great. Especially when bobs bots are up to 300% faster than vanilla, and that's before bot speed research has been taken into account. What I'm saying is, bobs top tier belts require end-game materials, and by the time you can make them, bots (especially bobs bots) are far superior to bobs belts anyways. So what's even the point of making his belts, even without Ultimate Belts installed.

So I don't want to put my belts behind bobs belts, since I want my first tier of belts to be available around the same time that bots become available. What seems like a much better idea to me is for my two lowest tiers of belts to override/replace bobs belts. This has been too hard for me to actually figure out, due to how bob is going about adding belts to the game. But if I could figure it out I would happily do it.

thanks for the response, this does make sense and I understand the points that you make.

Thanks for understanding! :)

Those points mentioned above are actually the very reasons that led me to create this mod in the first place! I felt bobs belts were severely lacking when compared to everything else he adds. Also, I really love using belts, but they just couldn't compare to bots. So in a few of my playthroughs I would be like, this time I'm gonna do a belt base. And the belts couldn't keep up, so I'd end up primarily using bots, despite trying to make belts work. So I decided I should find a mod with better belts, and then I couldn't find any. So I decided to make one! And it has become way more popular than I ever anticipated. I wish I could devote more time to improving this mod, but my time is limited and I don't play factorio much anymore :(