IMO, I would go with the 12" Tube. That will give you twice the smoke time.
I gave up on the electric last night. I talked to Masterbuilt today and they said that the heating element should *touch* the chip tray and that I should bend the element up to touch it.
What size tube do most people use?
Thanks for all the input.
John
The 18" is probably longer than your smoker's depth, and would limit the places you could put it in the smoker.
Bear