the need to sit furthur back is that because of long legs if so you could do as Wildmike did and move the control's forwardor if its to stretch your arms a little more why not shorter risers and a set of bars with less pull back,on my speedy i used 1" risers with a set of America bars works well for me
Benny

04 yellow&black Speedmaster+the Money Pit{xj jeep}