Is there support for extra tier loaders to match the 4 extra tiers that Ultimate Belts add? I just see the first 3 tiers of loaders.

I haven't added support for Ultimate belts, but I suppose that it wouldn't be too much trouble to add that support.

Cool, I will look forward to it.

I forgot to mention this back when I did the experiment, but unfortunately belt speed is capped at 120 items (for loaders) and so unless I do the same hidden-inserter trick that Therax does with Miniloaders, I can't support Ultimate Belts. Or the devs improve how loaders function internally (unlikely).

A recent change to loader logic in 1.1.28 allows faster-than-120 items/s (exact cap unknown) but I will do some tests and see about adding Ultimate loaders.

I've added support for Ultimate Belts. There is a limitation with the Ultimate Loader if you attach a circuit wire to the belt immediately in front of the loader: item throughput in that situation will be limited to 240 items/s. Otherwise, with a splitter or underground belt in front of the loader, throughput is the expected 270 items/s.

And train loading is 120 items/s. Going to see what can be done about that.

Edit: I have a solution, I've got input into cargo wagons working for up to 720 items/s, now to do output...

Edit 2: The solution comes with dramatic performance hits, so I'm going to be experimenting with this for a while.