Bruce.
The choice of the model type is of course yours to make.
The percussion or cartridge Military Model Rifle is not what you see in the photos you posted of Jim Baker.
45-70 would be acceptable for the long (er) range shoots, but not for the Main Match Rifle.
Again, it is your choice. My suggestion would be opt for the main match rifle first. And depends on how much you wish to become involved with this sport.
My best,
Blair