Moving the main hoop onto the "step" is an excellent idea. So is makeing the horizontal bar (behind the 2 front seats) "C" chaped to allow the seat to move more rearward.
Watch how close you get to the door, as I had to "alter" the door armrests to get it right.
MANY photos here at this link:
http://www.dariusrudis.com/mustang/rollcage
