I've been trying to figure this stuff out for the last 40 gallons of flying my AMT 180 Kangaroo.. I have access to alot of premium valving and flow regulators and pressure regulators since I'm into high tech industrial automation pneu/hydr, and here are a few things I have observed. On a straight propane can from Walmart I need about 30 psi . Problem is with the heat of the sun the internal pressure in the can can exceed 100psi and then when cool can be down below 50psi. A standard air regulator as pictured above still cannot regulate well with such a varied extreme on the input side. I've tried the low budget approach and it still is not a set and forget. it is a difficult task and I have finally solved it for me, but it is way too expensive, it involves a high tech 2 stage pressure regulator ($180), with a course side screw adjustment that feeds into a secondary chamber with a fine adjustment screw..this is then plumbed into a patented one of a kind (not my claim but the OEM's) adjustable constant flow metering device ($150). This has gotten me to a set and forget setup no matter what the the temperature of the propane bottle becomes.... Just my .02 based on trial error approach

Another thing I found intersting on the subject is Festo has no ratings on their products outside their use with air. Atleast thats what my rep claimed.......They do have a nice miniature pressure regulator with a built in regulator in bars and has QD fittings on inlet/outlet that works decent, but still needed adjusting based on inlet pressure extremes. Hope to meet some of you @ Superman!!!!!! 8 days and counting.........