L-Joe;
I don't know, obviously, what sort of motor handle extension you're NOW using, but years ago I had a little fiberglass tri-hull boat of about 11' feet. I tried, every thing I could think of, at the time, to find way to sit in the middle seat and still run the 5.5Hp gas engine that I had.

Finally, watching another at a boat ramp, one day, I copied his idea of taking a piece of PVC plastic pipe, cutting it to the exact length that I needed, to sit where I wanted to, in my own boat and attached it to the tiller handle of my motor with a "corrugated" style radiator hose, with a hose clamp.
The PVC pipe was attached to the radiator hose in the same manner, then I simply "glued a cap" onto the end of the PVC pipe, where I'd be holding it.

Because of the stiffness of the radiator hose, I could very easily adjust my speed, shift into neutral when needed, etc. Steering was also very easy, because of the flexible joint. Later, I did this same thing with a couple of electrics I've owned, over the years. I should mention, that when I first tried this, I used a "smooth" style of auto radiator hose, but because of the smooth construction, when I tried to turn a tight circle, the hose would "fold/kink" and became a real pain. The corrugated style hose didn't collapse, when bent to extremes.
Maybe "looks a little weird", but it's light weight, CHEAP to make and it DID work very, very,well!??!
Just an "Ideer"