+1 on Virginia Jim's commentary, assuming he does, in fact, have a Shad (I suspect he does).
I've had one for years. I electrified it for LED lighting and have used it interchangeably between my C14 and my C10, when I owned that C10. It is good reliable gear that has served me well and has proven itself to be quite functional and versatile. I have purchased from Murph's, and when he didn't have the parts I needed, I've ordered through Shadonline. However, given my druthers, my first preference is always to order from Murph's whenever I can because of service, value, and fitment, and because if we're talking Concours, Murph's needs to fit into the consideration equation.
Still, there might be several items to be clear on, and it may be a good idea to contact Murph's first: 1) Shad's website indicates a change to the top plastic surround from clear to black. I don't know if this conforms to your aesthetic ideals or if this represents what actually will be shipped, but it may be worth finding out exactly what is what; 2) You mention Murph's rail kit for the Shad. If I'm not mistaken the rail kit is for mounting the top case on a C10. I used it with my C10/Shad combination and it worked perfectly. You can even add washers and longer bolts to get the top case to level out to your exact preferences. Again, check with Murph's to be sure; 3) The C14 uses a mounting plate that I see Murph's also carries. I've used this too, and it has worked perfectly, bolting directly over he plastic tail rack. Again, got questions, contact Murph's.
A final thought: The tail end of the C14 is lofty and constantly reminds me that the C14 is a big-boned gal. I throw a leg over the C14 to mount carefully stretching my leg out in the knowledge that I have to clear the side cases. Throw in the Shad on top of the rear rack and I'm kicking like a Radio City Rockette in my efforts to get aboard without my boot marring anything up too badly.
Good luck with your decision.
HTH
Ted--