Whatever sauce you use, esp. if it's sugar based - wait till yer close to the end of the cook. Most sauces will burn.
Rather than saucing it, you could baste it with butter. Or bacon grease - I get great results with that. If you've used a salty rub be careful with that though.
I prefer Carolina Treet as a marinade and baste, but I gotta order it online and I'd be surprised if it's available where you're at, I'm sure there's fine stuff in the grocery store, but I'm not aware of what that would be. Maybe start off with Sweet Baby Ray's and tweak it to your liking.
That's a big farking chicken btw! :shocked: