Originally Posted by Don't Let It Bounce
There was a FXP Prestige Team that was 102 sq " and 18x19. I used its CAP grommets for a couple of Satellite Tours.
But I have a vague memory, which at the moment I can't confirm, that the earlier Head 660s (I'm thinking specifically of the TXM, which I think was released after Comp Master) had a slightly thinner beam than the later ones (Prestige Tour/Classic MP, Satellite Tour, FXP Prestige Team), so the FXP CAP grommets may not help the OP. Posters better versed in Head lore may need to straighten out that memory, though.
Yep, Comp Master, Graphite Master, and TXM/Prestige Master are all 19mm. The later ones from the Prestige Tour/Classic MP, Satellite Tour, FXP Prestige Team 660 are a wider beam.