Again, I wouldn't step down after the reg. because it can alter your pressure to the carb. The regulator itself is sort of a restriction itself so you don't want one step from a big line to the reg. then down another step after the reg. Capiche?
That said, it would probably work OK as long as you realize that this is not the best way to skin the proverbial cat. Just make sure you are able to verify your pressure at the bowl (after your step) or you will be chasing your tail.
