David, most of us remove the smoke box before foiling the bottom. Just slide it off the element, and take it out.
LOL ... I do take the box out to foil the bottom but when I slide the box back into the smoker, the corners of the box catch the foil and push it to the back of the cabinet. To solve this, I have attempted to lift up on the box as I slide it back into the cabinet but the element guard does not allow me to get the box high enough to not catch the foil. I can only guess that the smaller element guard and firebox in the model #1 through #3 allows one to put their hand done on the foil and lift the box more so that this doesn't happen. Neither of which can be down with the larger box of the #4.
Thank you for the laugh though, the mental image of someone trying to put foil in the cabinet with the firebox still in place is pretty funny. I should have been more clear in my OP.
HaHaHa!!
You know, I read your OP 2 or 3 times, and it just sounded to me like you were trying to stuff foil under the box, with it in place! I rolled the dice on the simplest solution (you'd be amazed how many times a really easy solution eludes some folks), and pulled the trigger! I knew, after posting, that it was probably the other way around, but also knew someone might get a chuckle out of it, if I left it - so I did!