Coco has been raw fed since she was about 6 months old - she is nearly 10 now. Back then, there were no ready made raw foods and I just changed her over in one go. I never limited her to one meat to start or anything like that - just started with the mixed raw diet that she has carried on with.
Now, raw feeding is so much easier with ready prepared raw foods like Nutriment, Natural Instinct, Natures Menu and various others, and there is much more information and advice available too.
I am sure Toby will be fine on the beef - starting with raw is trial and error anyway until you know what suits your dog best.

Coco can't tolerate lamb as it gives her the squits, some dogs can't eat other types of meat, so you will learn as you go along.