Some of the links on this forum allow SMF, at no cost to you, to earn a small commission when you click through and make a purchase. Let me know if you have any questions about this.
All I can say is that cedar planks are very popular right now even for use in the oven. But, I have heard that you really shouldn't smoke with it. I'll let someone else chime in on this one. Too many variables for me to balance out.
We use cedar planks for cooking salmon, but not in the smoker. The planks are soaked for a few hours and the fish (usually) is placed on the planks then into the oven or grilled indirectly. The steam from the wood gives a subtle flavor, but the wood should only be lightly toasted not burned at all. Cedar when burned leaves a lot of resin on everything and pops embers everywhere. If you are looking for that kind of flavor try alder in the smoker. Works every time for me and I have switched to it almost entirely.
When planking the oils in the wood come to surface and effect flavor but when burned people have a reaction to the smoke that can cause problems like big red welts on skin and your throat swelling shut just to name a couple of side effects.