What de facto standards or otherwise exist that prescribe a style for freehand technical lettering?
With the ubiquity of CAD there is probably a diminished need for standardized handwriting. Technical lettering was not part of my undergraduate engineering training yet was frequently mentioned and occasionally required by professors. When "required"- the criteria presented were few; simply capital case, sufficiently 'black', and ruled (drawn on/between lines). I am aware that true or traditional technical lettering has much greater complexity such as prescribing the order of strokes for drawing characters and their proportion.
I personally have sought to apply block lettering for readability and general aesthetic in handwritten drafts, but for lack of formal training apply personal habits of using dashed '7's and Z's and serif'ed 'I's- all of which I suspect are faux pas. Nonetheless I'm curious as to where to look for historical consensus to develop my drafting.