We use the R907 from Campingaz in our VW bus and also operate the 400 SG with it.

There are several possibilities. You need a 50 mbar pressure regulator for the barbecue anyway, which is available in different versions. We have a regulator that fits the usual gas bottles and one for the Campingaz bottles (R904/R904). The Campinggaz cylinders have proved their worth in the bus because of their compact dimensions.