It turns out the Wall Boost strat wasn't all too difficult once you get used to it. But it's still difficult to get a fast enough one to beat the record. But after a bit of grinding I beat it quite decently! I don't see much room for improvements here, since I not only got almost 4,100 u/s Wall Boost, but I did it super early and quite near the end of the platform. So in my eyes this looks close to perfection!