I'm 6'0" but I'm ALL torso so I sit pretty high. I had Bride FG rails with a Bride Zeta III. Swapped to planted and it dropped the seat about 3/4".
You can go literally as far back as you want. There are just 2 pieces of metal that meet together and you have to drill where you want them to sit. Very custom, not adjustable.
http://zilvia.net/f/showpost.php?p=5...&postcount=300