Recipes depend on the type of shooting you'll be doing. Are you going to use the load for hunting only or also target shooting? What is the biggest animal you plan on using the load for? For instance, if you are using the 300WM for animals no bigger than Antelope, I'd suggest something around a 150 grain bullet. But if you are going after elk or moose, a minimum bullet weight I'd recommend would be 180 grain, but prefer something around 200. The heavier bullets will also work well on the smaller game. Pick a bullet that'll fit your application, and work from there.
As far as powder, I've used RE-22 and Hodgdon 4831sc with great results. My primers of choice are Fed 215M for the 300WM. Consult your preferred loading manual, and work up with your powder charge slowly, watching for pressure signs, velocity, and accuracy. I've used the Sierra manual exclusively. The sendero is a good platform and I think you'll find it to shoot rather well.
Geb