Interesting that m4s are the tire of choice, in my experience clay coumpounds definetly seemed to react better to sauce than m4 or ss. You might try gold dirtweb/smoothys or some mc primes. Dont be discouraged if they dont work right away sometimes they need to scrub in first, you can help that along with a 80grit sanding block.
Have never found a better suace for Jc golds than blue can LW, dirt cheap also.
Have you noticed any adverse effects from using the LW? I have used it and Sticky Kicks on our indoor track, but people were telling me that the LW would swell the tires. Traction was great with it.