i use the scotty speed tubes (basically just a piece of pipe that the handle sticks into)...on the front seat i cut a hole through the triangle of alumium and used a flush mount. for the rear seat i removed the aluminum crossbar and put in a wooden one so i had a nice flat surface for my multitude of tools/electronics/mounts. i used the pyramid mount and bolted it to a small board. i used industrial velcro to make straps for the board. i used some contact cement to mount non slip mesh to the bottom of the board for no slippage.  i can move this rod mount around on the bar and  the rod holder itself has many adjustable parts to get the proper angle/height.