This is the method I use. It's from Gretchen at Cooks Talk Classic.
Gretchen's Pulled Pork

My recipe is to rub a pork butt or shoulder with whatever rub you want or no rub or a mixture of brown sugar and black pepper. The pork can be any size.
Put it in a 250* oven for 8 hours. Pull the meat being sure to mix in the browned bits and fat.
Moisten VERY VERY lightly with a mix of cider vinegar with a little brown sugar.
Serve.
BBQ sauce is added at the table by the folks eating.

Carolina Pulled pork
1 pork shoulder or butt, bone in or out--any size--the cooking time is the same for a 3#or 8# piece.
BBQ rub of your choice or just rub the meat with a mixture of coarse ground black pepper and brown sugar. Let marinate 8 hours or overnight.
Method 1--IF you have a smoker that can control the temp (I have a sidebox smoker and can keep the temp at 200*-250*) smoke the meat for 4 hours, keeping the temp low. Then place the meat in a 250* oven for 4 hours to finish. It will be meltingly tender and have a wonderful smoky flavor.
Method 2 (and this is the one I have really used for 30 years). Place the meat in a 225-250* oven for 8 hours uncovered . I have often done them overnight. It will still have the melting tenderness. .
When ready to serve pull chunks of meat off and then "pull" the meat into shreds by pulling between 2 forks. Do not discard the fat--mix it in. enjoy, use it!!! The pork can also be chopped.

For a traditional Carolina serving method very lightly moisten the pulled meat with sweetened vinegar (1 qt. vinegar + 1/4C sugar and 2TBS coarse black pepper). It should be so little that you don't even know it has been added.

To warm before serving put the vinegared meat in a pan (black iron frying pan is good or Le Creuset) and cover tightly. Heat at 250* until heated.

To serve, offer bbq sauces, coleslaw (in the Carolinas, it goes ON the sandwich), baked beans, rolls, and banana pudding.


For BBQ sauce here is my tomato based (western NC style):
1 bottle ketchup (28 or 32 oz.)
1 ketchup bottle of cider vinegar
6 oz. yellow mustard
6 oz. Worcestershire sauce
1/2 cup brown sugar
3 oz. liquid smoke
2-3 TBS coarse black pepper
Tabasco to your taste

Simmer for 45 minutes.
If you use commercial bbq sauce I suggest diluting them 1/2 with vinegar for this use.
Eastern NC uses vinegar sauces--sweetened vinegar with 1/4C (at least!!) cayenne pepper OR black pepper. It is too hot for me!
South Carolina uses a mustard based sauce but don't know the recipe. The one in T&T from Big Daddy is a good approximation of Maurice's of Columbia, SC.

Note that for traditional pulled pork BBQ, it is served without sauce. Sauce is added at the table, if any is wanted.

I put a dry rub on the meat , let is sit in the fridge overnight wrapped up. then I brown it in a frying pan on all sides the get some caramelization. I cook some onions in the same pan then put it all in the slow cooker on high for about 8 hours. You will know when it is done cause it just falls apart. I don't add the BBQ sauce until the end beacuse sometimes I like the pork plain.

I can't answer your cooking time question, but since you mentioned wanting to freeze this, I recommend freezing the cooked pork in large, separate chunks (say, enough for a meal or two each) and pulling/shredding it after it's thawed. In my experience this helps the pork stay moist vs. freezing it already pulled/shredded.

Based 0n my experience, that's going to take 8-14 hours...kind of depends on how you are cooking it and managing the cooking temperature. Classic charcoal method would be to maintain 225-300 degree F temp until the meat reaches 200-205. Temp rise will stall around 160 for quite a while (see Meathead Goldwyn's amazingribs.com for explanation or more detailed instructions). I know people who will start the process in smoker or BBQ for a few hours then transfer to oven where thermostatic controls are easier to manage but I recommend the full outdoor cook if you have the wherewithal to monitor/manage temp within the proper range.