Hi I need help with finding the elevation angle a Fortec Star 90cm dish with a FC90U mounting bracket do I need to account for the offset angle on the dish to add or subtract from the elevation angle I need. My location is 40.748167 N, 74.049752 W and I'm try to get Galaxy 10R at 123.0. The other part to my question is on the mounting bracket I have what do I use to come close to the degree I need because there's no line on the plate to let me know where I need to be.