In a bowl, mix dry spices, sugar, and sea salt. Stir in molasses to form a dry paste. Rub paste on roast and place meat in a resealable bag. Marinate in refrigerator 4 to 7 days. Once a day, rub the beef well.
When ready to cook, place beef in pressure cooker. Pour in beer and cover with water. Close lid and lock. Set to "meat/stew" and adjust for 1 hr, 25 minutes. Press "start/stop".
When done, quick release and make sure all pressure is released before opening lid. Carefully open lid and check to see if meat is tender, but not falling apart. If done, turn cooker off and leave meat sitting in pot for 2 hrs.
Afterward, remove cooked roast and chill in refrigerator at least 2 hrs.
When chilled, remove and slice meat. Assemble sandwiches with beef, bread, and toppings.