I cut two mounts out of 3/4" HDPE. If you desire only one, you can just set depth of second mount to zero.
Leave blocks and tabs intact while drilling mounts.
I used a marking tool to draw centerline down back of mount and the mounting plate for positioning of holes.
Drill two holes (inners) with #19 drill (4.2164mm / .166") for use with M5 tap.
Drill two more holes (outers) to fit hardware of your choosing. I went with traditional wood screws.
On front side, drill another #19 hole lined up with center of rod holder (cutout) and tap.
For the clamp I chose a medium lag screw with hex head and flange. Drill appropriate sized hole for screw and larger drill for the tab part of clamp.
Clean up tabs, bore should be smooth for router.
Mount on backing plate, adjust slide as needed, and enjoy!