box size ?

[mcbuggin 1]

well I have a single BTL18 now and was wondering the smallest box that 2 could fit in or if I might want to look at 2 15's. I have 36X30 for a box now and wondering how tall I would need to make it to fit either 1 more 18 or 2 15's also would like the tuneing around 35. If someone can help with this it would shure help. Thanks