To secure the mop in the PVC simply insert the mop handle in to the PVC and drill a hole through both then insert a bolt through and nut the end. For added stability rotate the bolted assembly 90 degrees and one inch below from the first hole drill another hole and bolt that one. Hose off the window as you go along.We've had a few discussions regarding your hint and tip, and I'm hoping hubby runs with it.
If we had such an apparatus or even a proper squeegee extension rod for such, I could even clean the windows, and rather than twice yearly, I'd be doing them once a month.
I appreciate your post, FM!