Porch awning edge to window - any problems

Tirril

I am about to buy a porch awning and have narrowed it down to an Isabella Magnum 250 Coal. However the length means that I will have to run the rear right side rorner midway across a rear window (on a t/a Barcelona). I could buy the next size up but eventually I will change for a shorter single axle so prefer the size of the 250. Has anyone suffered abrasion damage to windows/panels from  porch awnings. In the past we have used full size without problem but have never found they fit the next caravan.