I have a 38FLSA and attached pics show where I mounted mine. This location is directly above the fireplace and TV and allowed me to route new cable through the same ceiling hole as the TV antenna cable already went through. Unfortunately most other floor plans, this location is above the bedroom closet. That may not be a good location for cable entry.
The most difficult part of installation I found was the Wineguard instructions call out maximum gaps under the base. The roof on the RV is crowned everywhere. I made a base from Luan, Balsa core, and fiberglass to provide a level and stable mount. This base is 3/8" thick near the rear inside section and has a max thickness of 2.5" on the outside edge.
I think the base worked well and could be used on any model but the cable routing I used will probably be of little help unless you have the same floorplan. If you do have a 38FLSA or just have more questions about how I did my installation let me know and I will try to help.
Cheers and happy glamping!