I'm not saying that all of them will dock perfectly. The ones that I have had experience have been awesome around the dock. They were quite a bit smaller than the Magnum you are talking so about, so maybe that has something to do with it. I am certainly no expert on them. I'm just relaying my experience.
Eddie

the closer together the props are (staggered v bottom), the worse they dock. The further away they are (side by side or even a cat), they better they dock. They have more leverage in that sense. Our boat has staggered #6 drives and it docks like crap.

We really need to put the Arneson docking issue to bed. They are absolutely fine around the docks, no different than any other drive in the same application. Any boat with close drive centerlines are more difficult to dock than with drives being further apart, as stated earlier.

I have experience with an old boat converted from TRS to Arnesons, and if anything, it feels better around the docks.