Thanks for the link and OP! Good question and the answers make me feel very silly.
I was told a long time ago (by someone who SHOULD have known!) that the winch number was the manufactures rough estimation of the length of boat for which the winch would serve as a primary. It wasn't really an issue for me, so I accepted it. However, I often wondered why my Lewmar ST 40's (and me) sometimes get worked in a good blow on my 30 foot boat. I thought: "I'm not exactly a small guy, and 40's should be overkill!"). I could always head up, but thought that I shouldn't need to with my guns and the mighty ST 40's.
Now, I can stop fighting it. Whew....what a relief! (no ego here!)
I do wonder how they match the winch to the probable load. Is there a formula for sail size to winch power ratio?
I assume the power ratio on the chart is for low gear (on two speed winches), as they would want to rate the most power you could expect from the winch, when push comes to shove. Correct?
Regarding the winch service issue: I found a small plastic bucket in the paint department at the hardware. I cut the bottom out and it fits nicely around the base of the winches to retain parts when I service them. If it needed to be bigger, I could have removed more of the lower section of the bucket to fit.