I thought I read some posts before (can't find them now) about seats taller guys have found comfortable for wide glides. I'm always trying to push back to get more leg room.
I got the Corbin Solo Classic and that puts you back at least 1" maybe 2", and lowers you about 1". If you like solo seats that is. I think Corbin will also custom alter any of their seat styles, maybe give them a call.
I'm about 6' 3" and put the LePera Daytona Sport on my Wide Glide. It seems to give about 1 1/2" - 2" of extra leg stretch over the stock seat. That seat along with 3" extended forward controls has me pretty comfortable.
Just like Harley makes "reach" seats for the vertically challenged, they also make tall seats for those with longer legs and arms. I know they have them in their catalog for the touring models, not sure about the Dynas. I'm real happy with my Mustang Solo wide touring seet. It is about an inch taller than stock, and sits you a tad farther back.