Hi Steve - welcome to the party! 8)
I use the same method I do for baby backs, but spares can take a bit longer (maybe 20-30 minutes). Remove the silver skin, slather in yellow mustard and rub, then wrap in plastic for a sit in the fridge to get happy.
In the smoker @ 235, pan of apple juice on the bottom (next to the smoke box), 2.5-3 oz of wood, then let them go for 5 hours without opening the door. At 5 hours, check for doneness. You can't probe ribs - not enough meat and too much bone to get an accurate reading. Ribs are all feel and appearance. Use a wooden toothpick between the bones. If it goes in tender, and the meat pulls away from the bone without breaking the toothpick, they're done! No need to foil, spritz, or anything. Just let the smoker do what it's best at - Lazy Q! ;D