OK, I was waiting for the experts to reply, but I don't want to leave this without a reply for long.
Use the acetylene regulator. While there are dedicated propane regulators, the only adjustable ones I've seen will require separately installed inlet and outlet gauges. I would guess that almost everyone uses acetylene regulators. (Edit: I found propane regulators with inlet and outlet gauges. They are more expensive and harder to find.)
Having said that, do not use acetylene hoses. I have read that their rated life is reduced by half due to deterioration caused by the additive in propane (e.g., 5 years vs. 10 years). Acetylene hoses are "R" rated hoses and you do not want those, you want the "T" rated hoses.
Also, you did not mention an oxygen regulator. If you are using a bulk tank with a Hot Head (i.e., not using oxygen), a regulator is not necessary (the correct setting would be somewhere around 80 - 110 lbs).
Also, you should have a flashback arrestor (check valve).
"Grade R for acetylene only. Tube and cover are not flame resistant and not oil resistant.
Grade RM for acetylene only. Tube is not flame resistant and not oil resistant. Cover is flame and oil resistant.
Grade T for most fuel gases, including acetylene. Tube and cover are flame and oil resistant.
Oil Resistance: When exposed to an oily environment, Grade R hose may become soft and tacky. This may lead to hose cover separation from the reinforcement, or excessive wear of the cover.
Flame Resistance: Grade T hose has a self-extinguishing tube and cover that provides external and internal protection against exposure to adverse conditions such as hot slag, flashbacks or inadvertent flame exposure. The cover of Grade RM provides only external flame protection, and Grade R offers neither internal nor external flame protection."
The lower cost of Grade R and RM hoses, as compared with Grade T hoses, makes them attractive to buyers; however, the differences between the grades, and the consequent potential for premature failure, create the possibility of choosing the wrong hose for an application. Due to these safety concerns, CGA Safety Bulletin SB 11-4 (2004) recommends the exclusive use of Grade T welding hose for all oxy-gas welding applications."
Here is another important precaution from the same source:
"On rare occasions, old or improperly maintained oxygen regulators will ignite. But even a new oxygen regulator can burst into flame if the cylinder valve is suddenly turned on full. The quick burst of high-pressure gas from the cylinder into the regulator recompresses the oxygen inside the regulator and heats it to several thousand degrees Fahrenheit. Oxygen cylinders with regulators attached should always be opened slowly."
Here is more explanation of acetylene and propane regulators (i.e., acetylene regulators can be used for propane, but not the other way around):
VERY IMPORTANT: Do not run a propane regulator on acetylene.
Acetylene regulators contain special gaskets that are immune
to the solvent fumes found in acetylene. Propane is purer,
so propane regulators do not need these special gaskets.
Acetylene can ruin a propane-only regulator, cause leaks,
and otherwise cause danger to the user.
By reading the specifications for regulators from a manufacturer (Harris), it looks like (quality) propane regulators are rated for higher inlet (3000 psig) and maximum outlet (50 psig) pressures, while acetylene regulators are rated for an inlet pressure of 400 psig and a maximum outlet pressure of 15 psig. The pressures used in flameworking fall within the design range of acetylene regulators.