There's more room on our Zodiac, but we also have a 380 Aerotec and it is still just possible without any transom mods. Less steerage available (one way) and no reverse as the little Honda needs to spin round.
I think a long shaft aux. would work better on the 380 as you could bolt a riser plate to square off the sloping transom top at the sides.
If you're feeling flush a Torqeedo 1003 would be a good option as they are both light, skinny, and modular.
I can appreciate the extended floor tabs causes you additional problems and the need for an outboard bracket - some of these annoyingly rattle badly by the way.
My post really was just to say it is possible, though not ideal, to carry an aux in the boat and mount it on the transom while at sea if required. We've only tried this as an excersize though, albeit in quite a swell, and may not be as easy in an emergency situation.