You use your trolling motor more than your big engine when bass fishing, so buy the best you can afford. You need the 42" shaft to keep the prop in the water in waves and 80+ thrust is there when you need it. I moved recently and no longer have my 26' depth garage, so scaled down to a 17 1/2 boat with swing trailer o fit into 19' garage.I don't fish big lakes or tournaments anymore the 17 1/2 OK, just need to get used to 50 mph. My trolling motor is a MotorGuide Tour series digital, 24V, 45" shaft, built in transducer. This combination works great on my boat and wouldn't have anything less. I may up grade to a wireless with the GPS anchor feature next year if they are reliable and get a chance to fish with it.
Tom