I doubt it is ruined. Your method of stretching looks good but you can't actually install the top that way. You have to hook the front of the top over the lip on the windshield & clamp and then make sure the bottom of the top legs are slid as far forward as possible and then snap the rear snaps. I usually try to stretch the center ones to fasten and then work my way one by one out & around to the doors. I apologize if you are already trying this but in the photo it look like you have fastened the rear and are trying to pull the front into place - OK to stretch the top material but not to actually install the top.