I have installed them in 9 bins ranging from 18' up to 54'. They are easy to install. The covers work well because there is less volume of grain to move and you don't snag every flashing bolt. Yes you have to use existing flashing bolts they do fit tight against the wall. Me and another guy did a 42' roughly in 3 hours. For guys who raise seed silicone can be used otherwise unnecessary. Some kind of foam pads or knee pads are a must for installation. I have tried a leaf blower and found it creates too much dust.As far as cost I found it to be very cost efficient per bin in my opinion.