10T or 12T MAC motor?

I am trying to put together my first e-bike. I plan to convert my dual suspension Giant NRS-1. I plan to do my commute (17 miles roundtrip) on this bike. I am what you would call part of the "lycra" crowd and was riding 50-110 miles/week on my road bike before I developed a disc herniation in my neck a couple of months ago. The best way for me to ride now is more upright, so I put a riser bar on my mtn bike. The suspension and the tires also smooth out the road. Converting it to electric sounds like a fun project and I think it will give me nice options of not doing all the pedaling work myself and/or going faster.

My commute is about 1000 ft of climbing over 17 miles. Most of the ride is pretty flat, with uphill sections of mostly 3%, but with 2 short segments of 200-300 feet of 8-9%. I weigh 138 lbs and hopefully my e-bike will be about 50 lbs when I am finished.

I am looking at getting a MAC motor and a 50V 10aH LiFePO4 battery from EM3EV. I have done some simulations on ebike.ca and I am wondering if the BMC V2 torq is closer to the 10T or 12T MAC? I am interested in the 10T if it meets my hill climbing needs because it would give me a faster top speed. Thanks for your help! Any suggestions or comments are welcome.

My gut reaction is that you'd be delighted with 10T under circumstances you describe.
I have 10T setup, with 50V 12Ah NMC battery, set via CA2.3 to draw no more than 30 amps.
It eats short/steep hills like you describe, especially with a bit of input from the rider.
If you're a lycra, you've got the leg muscle to do the input... but likely with this setup,
you're going to become lazier and lazier, and eventually only pedal to keep up presences :lol:

On the flats, with moderate throttle and some reasonable pedalling, amazingly efficient setup.

The hill you describe won't require the 12t at all. 12t would be for extremes, like very steep horse trails, stuff way above 10%.

Get the 10t for sure. With pedaling, 10% for miles would be ok.

A motor doesn't have to make you lazy. Set a speed, then pedal up more speed to your desired heart rate. Easy to still put in 200w continuous effort. Well, not easy, 200w pedaling is hard. I just mean that it's quite possible to motor along and still pedal just as hard as you want, provided your bike is geared high enough for it.

Get the 11t freewheel so you can do a higher speed peddle. Plus order a torque arm.

10t will do it easily. Especially with your weight. My 250lb self could probably pull that off with an 8T.

You'll be plenty happy with the power, if you're fine doing under 35mph speeds

I really appreciate all the comments. I think I will go with the 10T and the 25A controller, 11-28T freewheel and some torque arms.

I will probably still pedal a fair bit. Strava (GPS bike app) was estimating I was averaging 100-130 W on my commute, with peaks of up to 300W. I don't know if I can directly compare those numbers to the numbers a hub motor would put out. I will definitely need the motor's output as the bike I am riding is going from a 20 lb touring bike to a 50+ lb e-bike.

I park my bike inside my office, so I could recharge there, but I don't want to burn through the battery cycles too quickly. I think a 50V 10aH should work. I am planning on getting CA 2.3 to help me figure out how to be maximally efficient.

I see they have some interesing mid-drive mtn bikes coming out next year. I suppose I could wait, but they seem like they are going to be very expensive. I love my Giant NRS-1 and it is set up perfectly for me, so it seems like a better idea to convert it.

Charging more often does not "waste" cycles. You just get extra cycles if they are shallower. So charge whenever convenient.