Yay, it's still a shame this version isn't a little more polished / finished because the track itself is much much more accurate than the MobaE everyone is used to . Good find.
I also found the other day that the most popular version of Ebisu Minami is pretty inaccurate as well, a more accurate version is the one labelled 'Ebisu Circuit (Minami)', which was supposed to become the entire ebisu complex on one map but I guess it was never finished . Note that both minami's have scale issues, but one worse than the other. I'd guess the reason one is more popular than the other is because the one we're used to has the school course finished with it.
Yeah, it's difficult since modeling just about anything is like a puzzle putting the pieces together until they fit, but given the references we can obtain nowadays online, at the very least it should be on the correct scale. I have no idea when these minami's were made so I can't really judge them specifically
The more references for whatever your making the easier it is to be accurate, so for my own sake don't bark at me if my touge ends up a mess