Sorry for the late reply to your questions. The position of bottom vent open approximately 1/8", just good crack. Smoke quality was fine. Attached temp unit prior to fire building, with dinner plate holder I purchased with unit. Followed chart from tiptoptemp website which proved to be very close. I loved the simplicity of the mechanics of it. For the money I spent it has allowed more watch free smoking, and chasing temps. The thing seems to almost sense temp changes quickly and compensates. Good luck to you.