+1 on droptrd and rbailey. Vintage 30, that's speaker all Mesa users have, a lot of people who play "kid metal" use, and you see BB posts "trying to dial out this upper mid spike..."
Also, Scumback M75, uber choice, available in 65 and 100 watts for your RM100!
Would like to hear the newer Eminences on a Marshall. I have the Splawn Eminences on my Quickrod, where they work great, but not for everything!