I've bought a couple of whole boneless blades ... 20+ lbs ... might be the same as a 'shoulder clod'
couple of tips I can offer:
Split in half .... 10lb chunks gives a nice smoke/bark to not ratio, they don't take as long to cook when split either.
Foil at 160ºF then back in the smoker or oven. Use about 200ºF internal as a temp guideline. I use the oven at 275ºF until it feels like it will just fall apart in my hands. This is usually 3 or 4 hours after foiling for me. Rest it for at least 30 minutes before pulling.
If it's tough to pull, greasy and stringy it wasn't cooked enough.