May I have your advice on two PV panel mounting questions, please?

I've been surfing through past postings on optimal angle of tilt for PV panels, in order to get the most out of a system for my new off-grid house. It's in eastern Ontario at 45 degrees latitude. I see two tilt angle camps, one using latitude + 15 in winter and latitude - 15 in summer, or just stick to latitude for a fixed angle all year. The other camp says it's worth going into a lot of local weather issues, in particular citing the map on page 6 of http://oldweb.hawaiirdp.org/hetl/Ad...r-3z13.pdf .

That document and map provide an optimal annual tilt. But for an off-grid application, I understand you should calculate your needs based on the month with the lowest # of sun hours per day, not the annual average. Here's my question: So similarly, doesn't it make sense to set the panel angle at latitude + 15 for a northern latitude such as mine? My reasoning is that if I'm sizing the panels to meet most of my December needs, then I should be fine for the rest of the year, since the lesser summer power due to my high angle would be offset by the longer summer sun hours/day and the reduced power needs in summer? (I also want a high tilt angle in winter to reduce snow clearing.)

I'm planning on a roof mount, using a rack to bump up the angle from my roof slope (4:12 = 18 degrees). I've got full 8 am to 4 pm sunlight. The south face of my hip roof actually faces 12 degrees east of true south. The house is mostly earth-sheltered so no summer AC is needed.

My second question: I wanted to put the panels along the south roof eave in order to easily brush snow off (we often get sticky snow here), but I understand from searching past postings that wind stresses at the eave make this a bad idea. Are there similar stresses at the roof ridge? That's my second choice for mounting, since I can easily step up onto the north roof face from the earth berm and brush from the ridge without risk of sliding down the south face.

Thanks in advance for your thoughts on these two questions.
...Terry