Anyhow..
90" high in 14th, seems sufficient in my experience.. which is what a 61~2" 11th (the direct gear) gives..
[the 38:16x26, & 53:16x20 are both in that range]

I just leave it as is.. only have a chain tensioner on the biFri because, since the rear folds,
and the hinge is behind the BB, there is some slack to deal with..

both are doubles but, just 1, toothed, chainring.. the 38t is Stainless Steel by Surly..