There are 2 mast sections on a 192. Either a Z-spars mast, which is flat across the aft portion of the extrusion, where the slot is, and the elliptical shaped Dwyer extrusion. Z-spars equipment can be found at
www.rigrite.com, and Dwyer at
www.dwyermast.com. Dwyer spreaders are aero shaped extrusions. I couldn't say what the Z-spars spreaders look like, or lengths for either. My Dwyer spreaders are currently under cover, but if Rudy doesn't have info, I could get to them eventually.
My experience dealing with Rig-Rite for my old Harpoon spar parts is that they are extremely unfriendly and reluctant to be helpful with anything. This is corroborated by my friend's experience getting a new mast step for his 192 Z-Spars mast. I don't know what their problem is. I've had much nicer conversations with Dwyer and of course Rudy at D&R.