Untested - Damson-glazed roast pork

http://www.geniuskitchen.com/recipe/plum-glazed-pork-tenderloin-161736
https://www.allrecipes.com/recipe/9253/roast-pork-with-maple-and-mustard-glaze/
http://chefdruck.com/2012/09/brown-sugar-balsamic-glazed-roast-pork/
https://cookthestory.com/how-to-roast-pork-perfectly/

Ok, this is a whole experiment! Here's my rationale. I want to use the damson jam I made with pork, but I don't want to slow-roast it. From what I can see, glazed roasts are first roasted, then glazed and roasted another 30 minutes. High temp roasting means the roast is first cooked, then put back in the oven for 12-15 minutes. It seems to me that this latter method should work with glaze just as well since it's half the time. So here's my version.

3 lb bone in pork butt or pork shoulder (or calculate for 40 minutes x lb)
1 clove garlic, cut into slivers
1 tsp salt
1/2 tsp pepper
1 Tbsp vegetable oil
1 cup ? chicken stock
1 cup damson jam
1⁄2 cup dry white wine
2 tsps minced fresh rosemary
2 tsps brown sugar
1⁄2 tsp salt

30 minutes before baking, take the pork roast out of the fridge and let it sit at room temperature.
Preheat oven to 300°F.
With the tip of a knife jab slits over the roast and slip in the slivers of garlic.
Slather the roast with oil and sprinkle with the salt and pepper.
Put the roast in a large roasting pan, fat-side-up. Add about half an inch of chicken stock (how many cups is this? to the bottom of the pan. Add more if it completely evaporates, a half-inch at a time.
Put it into the oven, uncovered for 2 hours (or about 40 minutes x lb). NOTE - the ideal internal temperature is 180F for meat that is properly cooked but not so tender that it pulls when you try to slice it.
Take the roast out of the oven and transfer it to a plate. (You can save the juices for gravy on potatoes or in a meat pie in another recipe). Let the roast rest for 30-40 minutes. This is important because this is the only time the roast will rest. The roast does not need to be covered during resting time. Don’t skip this step. Use this time to make the glaze and to finish off the other side dishes and set the table.
For the glaze, combine the jam, wine, rosemary, sugar and salt in a saucepan. Slowly bring to a boil and cook until it's lightly thickened, about 8 minutes. Stir often to prevent burning. If it's ready before the pork has finished resting, remove from heat and cover to keep warm.
Re-heat the oven to 475F.
Once the roast has rested, the oven has preheated and you have everything else for your dinner just about ready, apply 1/4 cup of the glaze to the roast.
Put the roast into a clean roasting pan or onto a baking sheet, uncovered, and put it into the hot oven for 13-17 minutes or until the outside gets nice and brown.
Take the roast out of the oven and immediately carve it and serve it. Do not let it rest now since it has already rested.
Serve with the remaining damson sauce (What would the sauce be like if I somehow used some of the cooking juices from the pork?)