The way my buddy taught me to do this years ago (15+) was to get a whole top round and cut it into smaller roasts somewhere around 5# each. We use two 3/8" stainless steel skewers through the roast, 15# to a skewer set. Then cook it over charcoal in a pit. Our old pits were 280 gal oil tanks cut in half , cleaned and modified slightly. We used a mop sauce that was tomato, spice, vinegar, oil based and mopped it on as it cooked. Nice bark and because they were on skewers, you got well done to rare as they cooked. We sliced it to order.
Now a days, I use a similar mop sauce and I also marinate the roasts in the mop sauce over night for a little more flavor. That means I use two batches of it. The old pits are at a site 45 minutes from me so I am using my Meadowcreek PR 60 probably just on the rack, mainly because I am short on skewers and don't have time to run down and pick them up next week. I know down Baltimore way, they do not use skewers (at least where I went last). Of course, they did not use a mop sauce either, they used basically what I use on Brisket (salt pepper onion powder and garlic powder) which is good too. I hope to have some pron after next weekend...
KCBS CBJ Caldera Tallboy, Meadowcreek PRS60,Blue Weber OTG,2 UDS,and other Weber stuff