Check out this link on portaging pads. I just ordered myself a set of the thicker bolt on pads for my canoe. I have never liked the factory pads and my aging body has been telling me to find something more comfortable. I think this is the best solution that I have found. They bolt or clamp on to a ash portage yoke (depends upon what style you order). When you order the pads a drilling template is included I believe the yokes allow for 2" of adjustment.
http://www.gear4portaging.com/pages/180334/index.htm
http://www.gear4portaging.com/pages/180334/index.htm