Rack Suggestions for truck with topper

I initially bought some foam blocks and tie downs from NRS to start off with, but now am in the market for a better system. I have an older nissan truck with a topper. The topper has square metal racks that seem to support my kayak just fine. Is there a good product out there that I could add to my existing rack? I load by myself so something to make that easier would be great. I also own a plastic necky elaho, so something that keeps the kayak on its side might be good to prevent oilcanning. Thanks in advance for any advice.

Either Yakima or Thule
stackers to clamp on your current rack and some pool noodles. Slide your boat right up. Really great system. If you do not want to make or buy stackers, carry your boat upside down.

Where do the pool noodles go
Looking at the stacker picture on REI web page I wasn’t real sure where the pool noodles would be placed.

On your bars
next to the stackers