EZquilting makes a DraftnCut ruler that is 2" x 18" with 1/8" lines. I would use that. It will allow you to hold it still and has a 1/2" more so it would be safer for fingers than a 1 1/2". As someone said earlier I use strips of sandpaper on the bottom of my rulers. Just cut thin strips and make sure you put them where they won't cover a line you need to see. I just use a school glue stick. Elmer's glue stick is my favorite.
Joann's and Hobby Lobby carry this ruler. You can also find them online. I'm thinking they are around $5 each. I might be wrong but I buy these and cut them in half for my mini rulers.
It's not that expensive that you couldn't get one and give it a try and if that doesn't work for you no real harm done.
Edit: Here is a link for the DraftnCut ruler $4.59 plus shipping
http://www.simplicity.com/p-1478-dra...ol-18-x-2.aspx