I developed my drying oven control on my desk top using wires with alligator clips on the ends. I think the oven was 1500 watts or so. I noticed the SSR was warm after a long time of testing and rested it on a piece of aluminum plate. No problem.
The SSR in the oven control is mounted on the aluminum enclosure. Works fine for heat sinking. Heat is only generated when the SSR is passing current to the oven.
You can do the same.
Paul