I prefer the no feedback helm units. Also not impressed with the xtreme systems number of turns from lock to lock. The cable has very little free play but docking can give your arms a work out.
Look for a helm with the newer quick connect where the cable attaches.
To bend thin aluminum to a gentle curve just put some pieces of wood on the floor and step on in until it fits.
That hull corrosion looks bad in the pic. A patch with 5200 and solid rivets is a good repair in the right situation.
It doesn't sound comfortable to drive like that. I'm 6'3" and I can get my legs under the last 3 boats consoles I rebuild.
The smallest is my kids 14'
Take your time to get the ergonomics right and it will make every drive better
I would set the seat in and try your idea of steering wheel location before committing to anything. I picked up a 16ft to repair and my legs hardly fit around the console with the stock design.
I spend lots of quality time sitting in my 18ft Holiday planning where to mount things and still...