Thought this may be the only option. If you have time have a read of the following thread:
http://forum.miata.net/vb/showthread.php?t=521228
Some very good and detailed info.
I overheat my r888 after 10-15mins.but they still work - just a bit greasy.
I still have my medium fz201 in 205 to try. Optimum wheel width stated as 6.5j.