Possible source of the problem
Following suggestions made here & some of the recs I'd been given, I was gonna push the windshield forward. When I went to loosen the passenger side bolt that secures the gutter kit to the windshield, lo n behold there was no nut & bolt. A few months ago I had a familiar looking locknut fall to the PS floorboard. Looked around, nothin missing sez I & proceeded on my merry way. That was the locknut that held the bolt for the gutter kit-windshield point. I'm thinking this created the slack that allowed the windshield to get pushed back. When the truck passed me up deflating the top then got re-inflated in less than a minute, this slack allowed the bar in the channel to get sucked out & then the top comes off.
I did check the windshield channel it seems to be pretty straight & even all the way across but I am keeping an eye for that being a culprit too. I'll be looking for a new replacement in the meantime. I've done a few other things Chris/Badger suggested & still a couple others to be done. Lets see how this goes, will keep you posted. Thanx for all of the input.
Anything worth doing is worth getting carried away with(ancient druid saying)