I honestly do not think it is going to matter much. If you are nervous about them meeting then they will feel that and also be nervous. Your big dog will either tolerate him or he won't. I bet the pup wants to play with him and he will either play back or teach the pup to leave him alone. Its how he teaches the pup that you have to be worried about.
The other thing to worry about is how they play together. You will have to watch them and make sure that the larger dog does not play to hard with him. If he swats hard enough with them big paws he can cause some hip and elbow problems for your pup, so just make sure that they don't get to rough while the pup is small.
* (Swinging club) Whack! whack! whack! *
Nope, the old nag's still dead .