I have a MiniMax tug that I use for my Cessna 182. This has a 20V DeWalt drill as the motor. It definitively works better pushing uphill then pulling. I have a slight incline going into my hangar and it does fine. They make a version to fit the Grummans https://www.minimaxtugs.com/product-p/031grumman.htm
Looks like they have raised their prices a bit, it now list for $1400.
Advantages are it is light weight compared to the PowerTow, you can break it down in about 5 minutes and it will fit into the baggage compartment, and the drill can be used around the hangar for other projects.
My wife keeps nagging me to get one for my Grumman AA-1B, but so far I have no problems pushing it into the hangar.