I've only ridden standard Indys...
How are the hollows vs regular standard? This is my most curious choice
(Then .. the forged titanium vs forged hollows?)
I think I am reading that correct, 4 versions? (Not interested in mids at all)
Certainly a difference in weight and height, but unless you are a very pedantic or extremely sensitive in your setups, they are not going to feel overly different.
That said, standards are 55mm tall on the cast baseplate, anything the forged baseplate are 53.5 mm tall, so a slight difference in height.
For weight, it is about the same as a few coins in your pocket between the various options, so if you definitely need lighter, it will make a difference, but if you don't really need lighter, then it is not going to make a big difference.
I know some people who can really tell with their setups, but there are also lots of others who are not really impacted by it, and depending on how much you want to spend or whatever is actually available, it is still very much up to the individual.
I have skated and had them all, but I keep going back to the simple standard polished as they just work really well for how I skate and what I like, definitely more so than the lower Stage 9 and 10, which I still have on older setups.