On the Dyna forum I understand anything over 12" requires extending the cables- my 14" T-bars were perfect for me and any cost for cables were part of the deal if I wanted to ride comfortably.
That would look very cool but my personal opinion I don't really like the look of the passenger seat solo it up and it would be perfect maybe throw on a set of Vance and Hines short shots and your golden haha
Think of the bike as a blank canvas ready for the artist to pick up the brushes, each of us see something different on the canvas and that's what makes it so much fun to see everyone's bikes
With the new style rear fender HD now uses I don't like the solo look as much, with the old school fender it looked great doing a solo. I had an '05 NightTrain and she still had the 'proper' fender and a carb I set her up as a solo with a Le Pera Bare Bones, blacked her out, and used 20" apes and she looked fantastic. When I realized I didn't care for a Softail as much as I liked riding my Dyna's and decided to sell her I got my full asking price from the first guy to see her; mod your bike with a vision in mind giving the bike the flow you're after, see it in your head and don't stop until that idea is sitting in the driveway.
Sounds like you're ready, go get that Wide Glide and let the fun begin... and post up some pictures!