Recently installed a new single lever throttle/shift controller. The base of the device did not lend itself well to caulking as two of the four sides were not equipped with flanges. These two sides were simply rounded edges. I found silicone rubber sheet stock on line at Amazon. The package I bought had 3 sheets, 6" x 6" x 1/16". I was able to cut one of the sheets into a perfect gasket using the mounting template that came with the controller. I used my wife's sewing tools consisting of a rolling knife and a hard plastic cutting board. Once cut out I used a standard paper hole punch to make the fastener mounting holes. Installed the gasket with a small amount of compression and it looks like a good seal to me. I think the silicone sheet stock could be used to make a gasket seal in many places where the two surfaces are flat.
