First of all, Ted, I'd like to welcome you to the forum and to the world of cheesemaking. Even more than that, I'd like to thank you for serving our country. My son is also in the AF, stationed at Shaw AFB in South Carolina.
I had been using only the liquid rennet I purchased through Ricki's site, but am extremely low on it, so I decided to try Fank's hard cheese recipe. Where the culture is added at about 68* (don't quote me on the temps and other specifics, because I have a really poor memory and connection is too slow for me to speedily get it on here for me to check right now...). Then the cultured milk is allowed to set overnight before being warmed up and the rennet added. I had wonderful results with this method for hard cheese, so decided to try his mozz recipe.
I wasn't thrilled with the results - took forever to set up, then I had to wait overnight for it to acidify enough to spin. I decided to experiment with my next batch and used the hard cheese method of culturing the milk the night before, at a low temperature (I learned that if you heat the milk to 90 degrees or so, culture it with yogurt/buttermilk, and allow to set overnight, you end up with a HUGE batch of clabbered milk!). I then warmed the milk to the specified temp, added the rennet, and walked away for about an hour and a half (probably went out to milk my cow). There was a beautiful clean break when I came back. I followed the recipe the rest of the way and had curd that spun in about 4 hours, rather than the overnight that it took to acidify before.
I do need to add a clarification here - I am not using pasteurized, homogenized store milk, but raw cow's milk that is probably up to 4-5 days old. I skim off the cream (yummm - homemade butter), and make mozz (or any cheese) in 5 gallon lots.
I hope you are having better luck. I really wanted to be able to use Junket, as I don't have to order that and wait for it to come, plus it doesn't lose potency like the liquid does. I'm also in a position where I don't have to regret cheese mishaps/failures, as my chickens and pigs love it when it comes out inedible by humans!