Discovered this thread while trying to research a solution to a similar problem (though the reverse of the OPs).
I have a Parker 2320 and the Yamaha 250 is mounted on an "offshore bracket" that puts it about 3' behind the stern. It is a narrow bracket with no accommodation for mounting a kicker, so my only options are to (1) bolt a fixed bracket like yours to my transom or (2) use an adjustable mount.
I went for the latter, because I wanted to get the motor up out of the water without having to climb up over the transom and tip-toe out onto the bracket (I have to do that enough now as it is!).
So I purchased one of the the "best" looking brackets that Garelick makes (71044) and measured everything out only to find a couple of problems:
1) I have to mount the bracket inboard of the trim tab to avoid interference (at least thats what my eyeball tells me).
2) Doing so, puts the bracket (and kicker) about mid-way between the port side and the bracket on which the main is mounted
3) This far inboard, at max drop (14-1/2") the cavitation plate will not be in the position recommended by Garelick unless the lower mounting bolts go through the transom BELOW the water line.
4) Also, mounted so far down, I worry that the head unit will get swamped by any larger stern waves that roll in.
So I see my options as either:
a) Find a bracket that has more travel (Garelick doesn't seem to offer one)
b) Figure out a way to mount it farther out to port so that it doesn't interfere with the trim tab
c) Get a ridiculously long shaft motor (like a 30") which I have never heard of anyone having to do with anything other than a sail boat...
d) Mount it in a position so that the prop and intake are under the water line but not as far down as Garelick (and engine mfgs) recommend....
I wonder how many out there are running kickers where the prop is *behind* the stern rather than under the stern and I am just over-thinking this whole damned thing.....
BTW, I want the kicker motor for two reasons - first as a "backup" for island trips in case the main craps out on me I can still make way (albeit slowly) while I wait for Vessel Assist and secondly as trolling motor.
Here's the bracket I have:
Here's the stern of the boat: