I picked-up another short Losmandy dovetail plate for the C-5, but it's not so straightforward as using the Vixen dovetail. I'm going to have to make an adapter to mate the round casting on the C-5 with the flat plate. On the Vixen, the top of the dovetail bar is actually a pair of shallow rails, and the cylindrical tube nests right between them. Shouldn't be a problem, but it's another project. I also ordered the Parallax rings for my 6" Newtonian. This is my "Woodshop" design, with 1" secondary and low-profile helical focuser, optimized for excellent planetary imagery, with internal primary fan. If the Parallax rings are too heavy, I'll make a new set of PVC rings, modified to fit the Losmandy dovetail plate, since my current ring jigs are for home-made 1/4" thick aluminum bridge plates that are a tad wider than the Losmandy plate. If the mount will carry the weight, an ideal setup would be the 6" Newt with either the 4.25" f/5 Newt (vintage Jaegers mirror) or the 80mm ED or 100mm ED refractor riding on top.