Mainsail - answers to your points
After further review, solar will go straight to house batts for now. Back up will charge from alternator while switch is on both while motoring. Will be adding an echo or other charge back into the system later, but I think this will be good for now. (I am going to complete a wiring diagram this weekend and will post for follow up).
Size was based on the below energy budget (this is not yet perfect, but I think it is pretty accurate). My house bank is (2)75ahr for 150ahr total. I don't want to start with an excessively large/heavy panel, so I determined a 50-60watt producing roughly 3a will be good. Will be adding refrig and will parrallell a second panel in later to suplement when on anchor, etc.
Still determining mount. Will be flat on a pole off of stern rail. Am looking into an articulating head of some kind to point panel when convenient.
South Texas - 5 hours is conservative most of the year and probably accurate for the winter months. Lot's of sunny days. Would appreciate your opinion on the energy budget as a starting point.
Will be topping off the backup periodically by running motor on "both" in and out of the harbor, etc.
Advice taken on controller - will not go shunting as I need max efficiency with a smaller house bank (150). Will look into the recommended controllers. Thanks.
Will be looking into panel options from the reccommended vendors. Will verify warranty on UL solar.
Mount on pole on stern rail, up above bimini. Should be little or no shade most of the time.
Energy budget assuming a 60w that produces 3.1a at peak: