John, please don't think I'm being negative here, but its not immediately apparent to me what the purpose of this mod is – nice job that it is. I'm more than willing to learn something new if I'm missing the point!
Apart from using as a support for between centres work occasionaly, I mainly use the tailstock for drilling. Simply using the handwheel gives me a very fine degree of feedback on drill progress so never had one break. If using this long handle is for drilling, then surely the mechanical advantage could result in to much pressure applied to a drill, or a lack of 'feel' if starting to clog up with swarf? If being used for producing 100's of identical parts on rapid piecework, perhaps yes – but for hobby machining?
Again – please do not think I am critisising someone else's work, absolutley not. Just want to understand the thinking behind it.
regards