Well nuts! After researching this topic I discovered I was not unique, that in fact several others have attempted to use tape measures for a vertical antenna. My implementation is different but we need to give credit where it is due. I’ll do that first then explain my attempt.
In the November 2010 issue of QST David Poole AD9DP explores the possibilities of using a tape measure for a vertical and several for grounds. It is worth looking up and covers the basics well.
SteppIR (https://consumer.steppir.com/)- The daddy of adjustable verticals. You really can’t go wrong with one of these, if you have the cash. I am a little on the frugal side, but am saving up.
From the Web, Glen Thibodeaux KF5FNP, has a different take. He describes a method using a tree, keeping the tab connected to a stake. Worth checking out. Unfortunately I do not have any trees I can use.
UPDATE: we are building a replacement and will post it as soon as possible.