Interesting reference, Steve.
The linked page at Manchester Tank does clearly show a horizontal tank with OPD-equipped valve. It's also clearly apparent in the photo that the horizontal tank has distinct top side - although the cylinder shape is horizontal, the valve is still always on top.
Their Product Safety
page has a Helpful Hints
link, which has a nice clear section entitled...
CAUTION: USE LP-GAS CONTAINERS IN PROPER POSITION
The same page also addresses the use of 80% fill ports and weighing
for control of filling (FILLING YOUR LP-GAS CONTAINER
), which addresses the issue we discussed in the topic Propane tank Level?
. The dip tube (to 80% level) and port are what Manchester calls a "fixed level gauge"; note that these are not provided in all tanks, and in fact are not in any of the tanks I have seen for sale
in the Edmonton area (OPD or not).
Manchester Tank seems to be a good source of clear propane
handling information. Thanks, Steve.