Things to think about, its a low seat chopper in original condition, I dont know if you have GIVI windshield or not, but think like this, if you start with changing seat its simply impossible, if you want to do it right, as 2 screws holding it + passenger seat is attached with plastic L holders. Basically you would need new seat. Frame, soft part and leather, also in 2 parts as main holding is with 2 bolts.
Why I even mentioned windshield, I dont know are you calculating in miles or kilometers, but lets say when I was driving 90km/h with original windshield and I had a feeling that brick was thrown toward my chest, no probs now when using Givi. If you set seat higher, you might have same issue, brick effect. I am 182cm. Just thing to think about. Changing footpegs will not give you much room. as center of back break is still in same position. If you would mount right back break to your handlebar, like scooters have, then yes you can play with footpegs.
Only thing safely and nicely what is in my mind to do, could be this:
http://www.ebay.com/itm/CONFORMAX-TOPPER-EXCEL-ULTRA-FLEX-MOTORCYCLE-GEL-SEAT-CUSHION-AIRMAX-LARGE-/222085801601?hash=item33b5586681:g:RKEAAOSwd0BVsorC&vxp=mtr
I actually got more room for legs, by simply changing foam part in the seat, as it was 0,5cm now I have 3cm of foam and I can sit any part of the long seat, even in the middle of 2 seats connection and it does not hurt