In regards to the sizing problems noted by BPL : I ordered a size medium P-2 pack (19" maximum torso length) for my 18.5" torso and initially found it to be a bit small. The waistbelt was positioned at my belly button, rather than my hipbones, and I initially thought about sending it back for a larger size. Luckily, the hipbelt on the P-2 is removable and could thus be adjusted a bit lower to fit me properly.
From the pictures of the Conduit on the ULA website, it doesnt look like the hipbelt is going to be adjustable/removable, so you may want to think about ordering the next torso size up, especially if you're pushing the upper limit. If nothing else, rest assured that Brian is a great guy to work with, and he'll gladly allow you to make an exchange in the event that you ordered a size too small.