I am looking at a Johnson Seahorse kicker for $230 with tank and fuel fittings. It is a 25" model and I am a little concerned it will be too long. Seller says it is 32" from the center of the prop to the top of the bracket it would sit on. I mostly want it for a backup engine and would start by just using the I/O as an rudder to steer. The boat is a 19.5 Mark Twain VSONIC
Since I have never sized one of these before I figured I would ask for some advice. So I measured the lengths of back of the hull and provided the attached picture.
From the black bumper band to the sonar transducer is 34.5"
From the black bumper band to the flat hull portion in the green is 30.5"
From the black bumper band to the outside edge is 28
You can kinda see the waterline but it is basically at the bottom of the orange strap.

What do ya think too long? How are these sized generally?
Since I have never sized one of these before I figured I would ask for some advice. So I measured the lengths of back of the hull and provided the attached picture.
From the black bumper band to the sonar transducer is 34.5"
From the black bumper band to the flat hull portion in the green is 30.5"
From the black bumper band to the outside edge is 28
You can kinda see the waterline but it is basically at the bottom of the orange strap.

What do ya think too long? How are these sized generally?