Hello there and welcome.
I don't load for the Weatherby, but have loaded for the Win Mag for years.
Nosler Partitions are hard to beat. There are other good ones out there now, but the Nosler partition is the one other have been measured by for about 50 years.
If your Weatherby is long throated like they used to be, ya might check out the 200gr partition, other wise go with the 180gr.
Most likely, powders like IMR 7828, Reloader 22, H & IMR 4831, and other slow powders are what your going to find most useful.
The Hornady dies are good.
Note the instructions for setting up the Full Length sizing die. Hornady includes a "foot Note" below the instructions which makes their instructions much better then those packaged with RCBS dies.
However, depending on your rifle's chamber and the dies you have, you could still be looking at short brass life unless your dies are properly set for your situation.
Rule of thumb is to always size brass fired in YOUR CHAMBER the minimum amount that will allow the sized brass to again chamber in YOUR CHAMBER.
The problem here is manufacturing tolerences and how they can throw a monkey wrench into the mix.
If you wish to do so, send me a "PM" with your personal "E" address, an I'll send you a document explaining the situation and how to custom fit you dies to your rifle.
Offer go for anyone interested.
AS said, Hornady comes much closer to reality in their instructions then RCBS - who by the way also makes good products - but even they don't go far enough in explaining the situation.
Crusty Deary Ol'Coot