When I did my boat I asked the Outboard Dealer to get me a good one he actually got me one of these well very similar
Trem S/S Auxillary Outboard Bracket, Outboard Brackets | Mailspeed Marine
It is made out of a formed stainless steel plate and it seemed fine but when any pressure was added to the bolts to tighten it up it just folded further in so I had made some nice long bushes and fitted these with new bolts and sourced nylock nuts so now it can be tightened without bending the main frame, and now its fine no wobbles at all and it does exactly what it should.
I have had the aluminium type with the handle but that handle can get in the way.
ETEC
Trem S/S Auxillary Outboard Bracket, Outboard Brackets | Mailspeed Marine
It is made out of a formed stainless steel plate and it seemed fine but when any pressure was added to the bolts to tighten it up it just folded further in so I had made some nice long bushes and fitted these with new bolts and sourced nylock nuts so now it can be tightened without bending the main frame, and now its fine no wobbles at all and it does exactly what it should.
I have had the aluminium type with the handle but that handle can get in the way.
ETEC