I was told by a guy at a repair facility that as soon as a black motor hits the salt, it's on it's way out. The seals and bearings in the saltwater motors are made or that environment.
Wanting a smaller trolling motor is like waking up one morning and saying, "Man, I sure wish I had less truck". You can use less power than the max, but you can't add to it when you need it. If you are already set up for the bigger motor, that's what I would stay with. For the small difference in cost I would have a 36V but I didn't have a place to put the extra battery.
With what you are wanting to spend, you are limited to foot or tiller handle control. Before you nix a motor with I-pilot, you need to fish with someone who has one. The features far outweigh the price, especially when linked with the Humminbird and Lakemaster chip.If you are not running Humminbird, either brand motor will work. Unless I'm mistaken, MG does not interface with Humminbird.
2015 Seaark 1872 MV CC Etec-90
Helix 12 CHIRP SI, HB 1199, MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
Bitter Gun Owner