I am rather sceptical about this. Not because it's a bad model overall, but because I suspect the amount of fiat coming in does not correlate well to adoption. Namely, over-represented speculators must have vastly over-pumped the market, so it's hard to tell where we 'should' be at this point.
PQ=MV, M=k*n^2, n~r*exp(t)+f
Cheapness is near historical maxima. That's all you really need to know, if you think BTC is technically and politically evolvable to serve as, e.g. SDRs, with probability > 0.001%.
I had intended to be levering up about now, but in the event I decided to keep it down to about 80%, so that I can short stock markets (and bull-ride the faster-cycling bubble waves on MRO, with the small amount suited to its embryonic liquidity state) while we wait for the party to start rocking. At the dogleg I will lever up, if I'm functioning. Less than 80% sacrifices too much, takes too much risk, for my present taste.