Hello !
Since my last post, I've buy a 2nd hand 1m3 O/A setup (cheap, but the bottles won't last long).
I'm still trying to build an oxy/propane to run cheaper and complete the O/A, but really don't find a propane regulator around 1,5-7psi, not too expansive (under ~50€), and compatible with european propane tanks like that:

It seems it's a 1/2" left threaded.
So I've thought to use an acetylene regulator, as it's more common, cheaper, seems like it works quite good, with propane and I have an old one unused, but I still can't fit it on my bottle. I've search for adapters but don't find it on the net. Do you have some references or links ?.. Maybe use 2 adapters (bottle => 1/4" + 1/4" => acetylene) ?
Thanks for your advices

!