Would like to put a sunroof in and the Webasto model 790 was recommended to me. Laid out the glass measurements on a piece of paper and placed it on the roof and seems an awful lot of glass. There is also a model 740 which is 4in. less in length. This looks more better, I think. See alot of roofs on the forum but not much on actual measurements,(seen a few). Which model do you have? BTW, cost is $1300 installed for the 790. Thanks!