Morning Ross, BBQ bottles are designed to operate sitting vertical. That was all I knew until folks here provided some additional knowledge on the subject. Since most camp devices (as far as I know) are based on vapor from the propane off gassing and not the actual liquid. BBQ tanks can't lay on their sides for use or the vapor pick up tube is submerged in liquid.
Thanks to the folks here, I now know most fork lifts rely on the liquid in the bottle and not the vapor. So; internally, it's all about where the pick up tube is located in the tank. They do make some tanks that are vapor service only, others that are both and others that are liquid service only. I've found a few tanks on Amazon which are vapor service only $352.00 each.
I am trying to figure out whether or not the connection will work with standard BBQ connections. I doubt it, I believe the vapor connection is left hand thread. I am trying to get comfirmation from the manufacturer. Considering it's not likely to work, I believe this is why Joaquin had to have his custom made with the proper connection. If you have a nice spot picked out to keep your BBQ bottles vertical, you should have no worries. Myself, I am going to put one or two up under the box similar to the way Joaquin has done. I have a well protected spot for them under the box.