Harald @mx5-miata.no sendt me this link to the new SPEC miata setup guidelines.
They are now running Toyo R888 tires and has recomended setup instructions for this tire which is exactly what I have been looking for.

http://www.nwspecmiata.com/SpecMiataSetupGuidelines.pdf

I'm kind of shocked that I have been running way to little tire pressure. I ran as low as 24 psi hot on my NA and 27/28 on the MSM. This is based on tyre thread temps measured after a track session.
The Spec miata guidelines says minimum of 32 psi for a light weight car like the SPEC miatas... My car on the other hand is like 200kg + so I'm probably way off.
I wonder how this will affect 17" wheels compared to 15" they use.