I'm new here and I'm building a tow behind vertical offset smoker... I'm using a blasting cabinet made of 1/4" steel with a 40"x40" footprint and roughly 67" tall... I'm using a 28" diameter by 48" length oil tank for the fire box... Would it be better to cut the opening from the firebox to the cooking chamber in the side OR the bottom of the cooking chamber?? Can do either because of the way I am joining the two pieces...