Sounds like you have it under control. Any idea as to what sort of primer the Kynochs will have? I haven't been involved with any of their new brass or cartridges at all, I'm still working with a stock of Bell that I picked up years ago and is still going strong. RCBS 300 GC and 405 GC bullets work well in my rifle with IMR 3031 and CCI 200 primers. Horn would look good for the butt plate and grip cap, may be able to get it from Brownells or Mike's Outfitters (the old Cape Outfitters). Where are you in Va? I have a sister and brother in law in Bentonville, south of Front Royal.
Do you do any reloading for you 375 2 1/2? It's another one I,ve enjoyed.
Best.