Prepare an ice bath that can hold all the Brussels at once and bring 3 quarts of water to a boil in a 5-6 quart pot. In 3 separate batches, add the cut Brussels and boil for 3 1/2 minutes. Use a strainer or slotted spoon to transfer them to the ice bath. Allow them to chill for 8-10 minutes then drain thoroughly. This step can be done up to 3 days ahead of time.
Slice the bacon into medium size pieces. In a heavy bottom sauté pan render bacon until browned and chewy over medium heat. Strain and reserve bacon and the fat separately. Using the same pan, turn to medium high heat and add pecan oil and butter, or rendered bacon fat. As butter begins to brown, or fat begins to smoke, add Brussels sprouts cut-side down in one layer in the pan (it may take two batches) along with vinegar. Brown over medium-high heat for 6-8 minutes or until sufficiently caramelized. Reserve finished sprouts in a mixing bowl with the sliced sauerkraut and rendered bacon pieces. Toss and mix together and season to taste with salt and freshly cracked pepper.