Anything less than the 4000 is not powerful (mainly quick)
enough, and needs to be mounted further aft and outside of the toe
rail.
My version of solving the problem is as per photo – a lump of
oak holds the autohelm, and a new pin in about the centre of the oak
fits into the self steering fitting. Similar result as yours, but a
different way of getting it. Whereas the original 1000 was fine
motoring, and worked in some sailing conditions, the 4000 can cope
with most conditions. It also has the advantage of the control head
being next to the companionway (thus it is possible to steer from the
inside), and that the control head accepts NMEA, so can repeat a
certain amount of data, including GPS data, so a route set up by the
chart table can be viewed whilst helming.