Frame size is always a bit tricky. Stand over height is the most important as it should be roughly 1in shorter than your inseam for the best riding experience. If you’re caught between two sizes (Babymaker I & II: 19" or 23"), it’s best to go with the smaller of the two as it is easier to make a small bike feel big rather than making a big bike feel small.
*If you're a taller rider, check out this video of Dave, 6'6" rider on the 23" Tangerine Babymaker: