The 50mm one I got for my Trackman FX was a bit too small. I knew I'd need a caliper one day! You just can't measure these by eye, even at arm's length.
Not that it matters, the old sensor doesn't work on plain steel anyway. (Maybe sandpapering would help?)
Early days, though, my master plan is still "on track." :laugh: A properly engineered support system is my next step.