Once you get it to the probe-tender stage in the smoker, wrap it in foil and put it into a cooler wrapped in towels and fill the voids in the cooler with crumpled newspaper to rest. You can hold it there for several hours prior to serving.
Some wrap it in foil after the plateau is passed (after it gets to 165 or so and starts the temp starts climbing again.) Then they continue to cook it in the foil until it is probe-tender and then rest it in foil in the cooler.
Jim - Another transplanted Texan
Former KCBS CBJ
Large and Medium Big Green Eggs , Black 18.5" WSM, Blue Weber Performer - Stainless, Green Weber OTG Kettle , Brinkmann SnP Pro, and a Stainless UDS. One retired Portable Kitchen grill.
Red Thermapen, Maverick ET-732, EdgePro Apex Sharpener.
Avatar is the original 1951 Weber Kettle