Fairplay, but maybe get him doing what he needs to do first. Trying to train two dogs at once is a bit of a nightmare, and i bet you will favour one, and one will get left out, or they dogs will just take themselves off and ignore you. Spend the summer getting him fit, learning etc, and try it all out next winter, and if you really do enjoy it etc, THEN start to think about doubling your pack. You shouldnt get a dog you dont KNOW you have the work for, but of course its your call. I'd be very interested to see what your lad can do, i bet he surprises you.
good advice. start with the one