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.)