Downrigger question

FINALLY the chill is starting to break here on the Great Lakes!! My thoughts have been turning to spring coho salmon fishing here on Lake Michigan.

I have a pair of older Walker electric downrigger that I want to mount on my V20. I want to use the aft rod holders for quick mounts for the downriggers. Walker makes a mount that fits into rod holders. The trouble is the Walker mount is for a 30 degree angle, whereas my Wellcraft angle is less by about 10 degrees.

Any suggestions??