I'm sharing an adapter I designed for my quickie Mach 2 handcycle that allows me to mount my Wahoo element cycling computer. the way the bar was positioned on the HandCycle was suboptimal for any mounting bracket used by cycling computers. this adapter simply slides in and gives you a vertical mounting bar to Mount Your cycling computers/ phone mounts.
The vertical mounting bar where you mount the adapter measures 24 mm.
First, test print a couple of millimeters of the part that mounts on your handcycle to check your tolerances.