I play a HyWay club & use a Maltby FW club head cover on it. It fits fine. I just checked to see how my Maltby hybrid cover fits the HyWay. The hybrid cover will work though it fits pretty tight....
Love my set of M-45s. I just put them back in play. As statechamp stated - if they aren’t too beat up, get them. $50 seems a good price for a quality forged iron set.
I have a 2007 Golfsmith catalog that lists the Snake Eyes 600XC and all of the 600 series forged irons as 0.370" parallel.