Due to how different the is from when the first records are (more item types = less chance for “good items”, more item categories = harder time getting the type of item you want), thus I think that runs before a certain point should either A: be in a legacy category (I’d say pre the addition of movement items/when it was changed to 5 items per shop) or B: from the same time window as before, just make the runs count as “invalid” in some way (to not give advantage to older runs that where straight up less rng dependent)

I don't think this is neccesary, there may bit a little more resetting now because of new items, but I don't see it being too significant. Could you provide an example maybe?

The movement items surely would only make runs faster. (On ND especially)