I've been winching my Getaway on the trailer when the ramp is just not right (i.e. too short) without any problem. The boat is so light, I typically pull it by hand if I can't float it, but when the ramp is steep and short, I've use the winch with a simple wrap around the front crossbar. It comes up very easy with no flex so I think it's very safe.
Note: if the ramp is steep and you don't use the winch, make sure you still tie the boat to the mast support before driving up the ramp; I got a good scare when my Getaway backed off 3 feet on the trailer as I pulled up one ramp. I had images of the boat left high and dry on the hard going through my head, but got lucky and the boat kept balanced on the trailer until I repositioned it!