To my original question about size, they built my L and I went for a test ride. It seemed fine in terms of reach, but whenever I had to stand down, I resorted to tilting the bike because I would touch the top bar and that just seemed like a very uncomfortable accident waiting to happen. I tried a 4.0 M they had on hand and it fit fine in terms of reach and while I didn't touch the top bar, it was very close. Still, given the rider position was pretty much a wash for me, I wanted to go for the M instead.

The guy who was doing my bike adjustments and preparation (and test ride consulting) said the same thing as the original salesman - thinking I was 5-11 or 6-0, but no, I'm 5-9. I must "look tall".

We started talking about switching to a M and one of the other salesman said there was one over by the corner. Sure enough, they already had one built (5.0 SL EQ M). In the end, I went with that and am happy with the fit.

With regard to the SL being enough power for me... On my test ride I did try out a hill and I was getting pretty huffy and puffy, but I wasn't in the best gear as it turns out, so I didn't really see how much it could do. Still, I was managing. When I tried the 4.0 briefly I just went up and down their (rooftop parking) car ramp and it was clear that it had plenty of extra power if I chose a lower gear, at least as far as a car ramp went. That was enough for me - I'm getting this to enable me to deal with an occasional hill as I get back into biking, not as a either a taxi service or a fitness machine. I'm not intending to do long imposing climbs on it, nor am I wanting it to save me from all effort.

Test riding at home, I have some really steep hills right outside my house as I live on a large hill overlooking a valley. I wasn't able to deal with the really big hill right outside my house, but that is only about 100 feet long. I did better on the fairly steep hill around the corner from me, but by the time I got back I was really breathing hard and had to walk it all off. That may have also contributed to not being able to do the last really bad hill. It feels like I could work up to that and instead take the bike to a trail which won't have nearly as steep a section on it, for starters.

I took it down to the bay-front trail which has a few relatively short slopes of less than 1/4 mile in length. I was able to do them with my road bike a few years back when I was going to a gym regularly and I felt like I was doing better on them with no power than I would have imagined, but I definitely needed to turn the motor on before getting even to the top of the first one of them. I also discovered that assist level 2 is just about enough to erase the really strong bay-side winds you can get on that trail. I'd say the winds are around 15 MPH based on the fact that I was going about that speed on the downwind parts and feeling no air movement. On the return trip I was slowing down for a family with kids and dogs and another cyclist rode by on a regular road bike and looking like he was a fairly avid cyclist. I then decided to go out of "sunday/holiday" ride mode and try his pace. I pretty much kept up with him for the next 5 or 6 miles feeling only a bit winded when I got back to the car. That sounds about the right level of assist for me.