I use the skateboard tape. It only takes a couple/few small pieces to really keep the rulers from slipping around. I have a Tiara sit-down set-up.

If you are using your sit down as a sit down, which is what it sounds like, you don't need a ruler base, which is just for Long arm machines on a frame set up. I use handi grip tape on mine both on my Sweet 16 sit down and on my Longarm, although I find with the Longarm, you don't need as much "grab" on the ruler as I found I did when using it on the sit down where you are trying to hold the ruler and move the quilt at the same time.