I don't know if the "saddle" is a standard fitting on the 170. My boat was bought used. The previous owner only had it for a few months before putting it up for a consignment sale. While I can't prove it, I think he "turtled" in and that was enough for him. The reason I think it was turtled was that there was sand in the top of the mast that jammed the wheel that the halyard runs through. When the centerboard is all the way down, the short bungee that clips from the centerboard to this fitting is maybe 6" long. It's the same bungee that acts like a safety strap to keep the centerboard up if the line that also provides this service fails or comes out of the fitting. That line lock is what the "dashed" purple line in my picture is pointing to.
I'm sure you're right about it being much easier to step the Hunter 15. And you're definitely right about storing your boat out of the water to prevent "snot" from growing on it. I kept my 17 on a fresh water lake which does "crap up" the bottom during the 6 months it's in the water. A nasty chore cleaning it after the season for sure.
My personal opinion is that the Hunter 17 can be a bit scary when the wind picks up to the point where there is just a hint of white caps. A couple of years ago I watched a 170 from the shore turtle in those conditions. I wrote a detail posting of that on this board. Basically, when the boat turtled, the centerboard was retracted. I strong suspect the board was NOT bungeed down which probably added to the boat going "over" and certainly prevented the 2 sailers in it from righting the boat. It had to be towed to shore to right it.
Because of what I saw, I NEVER cleat my main sheet (especially on a beat) when the wind looks like it picking up. Several times I felt my 170 would have at least gone OVER if I hadn't been able to "dump" the mainsail by releasing the sheet.
On my "test" sail before I bought the boat, the wind was so strong we only used the jib and there were a couple of moments when I felt it was going "over". I'm too old for that kind of excitement.
While I sail my Hunter singlehanded almost all the time, I think it's much better to have 2 hands on board if the wind starts to kick up. One to mind the rudder and the other the sheets. And if there needs to be any on the water reefing, the sheet man takes on that chore as well.