The R4s are the same height (600mm) as the Falcon stands.
I have too many stands at present and the R4s top-plate matches nothing (it is designed for a ProAc 1SC, DB1 etc, so is deep and quite narrow). The Falcon stands obviously fit the 3/5As perfectly, they also fit the Spendor S3/5R if I rotated them 90 degrees, and are a better fit under the 149s than the R4s, but the baseplate still overhangs a bit.
I’ll likely sell the R4s as to be honest they are right on the limit, maybe beyond, what I feel I can safely carry up/down stairs on my own. I’m aware of my limits here, I very nearly killed myself carrying a Wharfdale Sand Filled Baffle SFB/3 upstairs a couple of years ago, got about half way up and just ran out of strength/leverage so ended up just standing there for a while with it propped against a stair wondering WTF was my next move! Can’t get it up, can’t get it down, can’t call anyone for help, don’t want to just drop it! Hmmm… Got there in the end a step at a time, but that could have gone very wrong!
The R4s are simply ridiculously heavy - anyone with a mental image of what a high-mass metal stand is just double it. IIRC they are about 25kg each. They are very good though, really amazing under the ProAcs they were designed for. The Falcons are far lighter so a lot easier to deal with, and are still nice stands.