Well the stock Flux doesn't allow for wide range of gearing either. :) According to the gearing app here, the standard 44/20 might be overgeared.
Anyways, thats why I planned on going with my own tvps (if possible) that use a center diff in a truggy layout. It'd basically have a whole in the middle of the tvp in which a larger motor plate would reside.
As the all-mighty Finn has noted, this idea will not allow a wide selection of gearing ?
Maybe the trans can be offset by a 1/4-3/8" by trimming TVP to allow this ???