Roller for Loading a Yak

Hello Folks,

I am trying to rig up my TracRac for 2 kayaks. I found these and they look good.

http://www.rackwarehouse.com/tracrac-44300-water-sport-complete-kayak-mount-rack.html

I was thinking it would be nice to have a roller in the rear since my truck is tall and I am not! So I found this.

http://www.oakorchardcanoe.com/suvroller.php

I know I could get something like that from West Marine or elsewhere.

My question is has anyone rigged up a similar setup with a roller in the rear? Will it hold the kayak secure enough? I have been looking in the forum but the only rollers I have seen are from Yakima and  I don't think I can adapt them to the TracRac system. \

If anyone has built a setup like that let me know since I don't want to re-invent the wheel.

I may call some rack people but they usually don't have much input about kayaks...

Thanks for any info!

Loren