Looks good, Mudd. I would, however, like to make a suggestion if I may. Consider moving the headtube rearward (until the pedal just clears the front tire), then shorten your 'tiller' some. (see modified image below) This will accomplish 2 very important improvements;
1. It will improve the weight distribution by moving the CoM (center of mass) further forward - resulting in improved low speed maneuvering and balancing.
2. it will shorten "TILLER" length - this will reduce the 'side-to-side' awkwardness during steering inputs, which will also enhance low speed maneuvering and balancing. (6 to 8" is about optimum.)
Thanks for the feedback PaPa! It's cool how you made the modifications. I knew that down the road I was going to consider shortening it. Can you use your program to see what it might look like with a remote pivot- indirect steering(oss)? Thanks in advance!