We had similar problem when we bought Josie our Springer x labrador home to meet Suki our Saluki cross. (We also had meg the yorkie at the time, but she was top dog and just growled at Josie so Josie kept away from her!)
However, we were really worried because of the huge size difference betwen Josie and Suki. When we asked the vet, he said so long as Suki lets go when Josie squeals, not to get involved!!!!
It has been really hard at times, especially when out on walks and Suki pinned Josie to the floor until she screamed, but Suki always lets go.
We had a bit of a problem when we lost Meg, as Suki was suddenly thrust into the position of top dog at the tender age of 18 months. She found it tough, and suddenly every time Josie came running into the room, Suki took to protecting us all from this young hooligan and went for her! We told her off for that as we felt that it was just OTT reaction to Meg suddenly going.
It has now settled down really well, and they play together brilliantly.
They are never left alone together (Josie still uses her crate for eating, sleeping and if we leave her) but now she is heavier than Suki, it is for their own protection as their games can get extremely boisterous and although they would never intentionally hurt each other, we fear for our house when they tear around together!
Best of luck, and I am sure it will work in the end.
Enjoy the puppy days as they go soooooo fast.