This is my experience as a 70 yo rider. I have a gravel bike with a 1000w BBSHD and a Tandem bike with a 500 watt, 48 volt , MAC front hub motor with high torque windings. We have a similar terrain situation as you do. A VERY steep 1/2 mile long hill that we have to manage when riding. On the tandem we dreaded that hill because we were moving at 3 mph and were wiped out by the time we got to the top. I got the front hub motor because it did not interfere with the very low geared rear chain rings and cassette. I added a front handlebar bag that would hold and hide the wires and the controller. It has a front throttle, cruise control and three speed settings.

The Tandem along with our weight adds up to around 300 lb. We approach the hill in our third lowest rear cassette and lowest hub speed setting. We try to contribute as much as we comfortable can to the effort and let the motor do the rest of the work. We climb up the hill easily and comfortably, usually averaging 8 MPH. We try to keep the RPMs up so that the motor does not labor. Since we did not mess with the bikes chain rings and cassette, we have lots of low end gearing to contribute to the effort. We love it and would never go back. The 500 watt motor has more than enough power and when we get to the top, the motor never feels hot.

The beauty of the front hub motor is that it feels like a regular bike except it's 15 lbs heavier. So when were just riding along we only use the motor as needed to get us over the lop de loos. It's also nice when we have to stop at a stop light. We can goose the throttle and get us going and thru the intersection quickly and safely. A Tandem is not the quickest when getting going.

Now to the BBSHD gravel bike. I've got a 42 tooth chain ring on the front and a 10 speed cassette on the back. It feels "more" like I'm riding a electric scooter and not so much a road bike. Even at the lowest assist level the motor somewhat spoils the bike riding experience. Since power is being driven thru the chain, shifting needs to be done with thought or else you can get a clunk from the drive train. The setup is definitely more powerful and can handle anything I can throw at it. If I'm not careful it can be a handful! Still it's a blast to ride, just different!

I purchased both kits from EM3ev.com. Quality products and good service

Hope that helps