RE-Introducing my cats to my dog!!!

I made the mistake of getting a Jack Russell puppy and just letting him loose with my two cats, at first everything was ok (ish) the cats would go for Jack(puppy) and just tell him off if he got too close. But as jack got bigger and bigger and bigger (I didn't expect him to be much bigger than a cat!) the cats seemed more and more unhappy with him, and started to come together and chase him to a corner and attack him, this was because he gets so excited he has to go overboard and the cats don't see it that way and obviously they get scared. So I had to keep them apart. I was going to make a tough decision cos it wasn't working out . I have since moved to my mothers, I still kept them apart and now i'm introducing them slowly and the cats seem completely fine with, Jack(now nearly as big as a Boarder Collie) as long as I keep him on the lead. One cat (Tilly the big boss lol ) she comes right up to him and they are nose to nose but I don't let him get excited I just keep giving him treats so he doesn't upset the cats and the other cat(Cassie) is so small and nervous, even she was fine walking past Jack . So I was wondering if I stay patient and keep doing this maybe it will work out after all. I'm gonna give it weeks and weeks, months if I have too. Has anyone else gone through it and been successful, you see people all the time with a dog and cat. I know the main reason it's because Jack has to play and he is too rough but even with telling off he doesn't learn the water spray helps but it only stops him then it doesn't stick in his head that he isn't allowed to do it.
A word of advice never just get a pup thinking a cat would just accept it and then grow up to be life long friends.