Shorter throttle arm?

I'd like to get a shorter throttle arm.

A photo of my existing one is attached. On my older (2009) MB, there's no arm rest (hence the black gel pad I stuck on top of the sidewall, which is a big improvement, but it's way too high), so I am working with a local service shop to try to get a custom arm rest made. But I think I also want the throttle grip to be a bit lower (maybe just above the black backplate in the attached photo).

I looked up throttle arms online and see various cheap ones, but I want a nice one that will last.

I don't have a trim tab switch on the throttle. (I am going to add a trim tab to my boat, but I was advised to keep the switch separate for less hassle if something goes wrong with the tab control vs throttle control... though I don't have much space for a trim tab switch on the dash.)

I also don't really like the existing throttle grip, since it seems to be screwed onto the arm and when fully tightened it's not straight.

Anyone know anything about this (and if it's worth getting the trim tab control built into the throttle)?

Thanks,
John