Our 40 Ocean has a R907 shaped bottle holder in the portside lazarette (from factory). Thought about changing it, but it would be a lot of work, so never did.
Turns out the R907 is fine. One bottle lasts us about 3 months with a bit of gas saving (like pre-boiling the pasta water in the electric kettle when we have power). Refills are available from various unofficial places between 5 and 15 EUR as well as the official bottle swap dealers (25 EUR). When going to Spain, avoid swapping a Genuine Camping Gaz bottle for a identical but differently painted Butsir bottle - difficult to get swapped back!
We have four bottles on board, one in the gas locker and the others in the sail locker. This is a separate locker, not vented, but not connected to the cabin either, only accessible by hatch from the deck. Not ideal, but the best we can do, and not caused any issues.
Camping Gaz appears to be the most widely supported format, so you spend less time in expensive rental cars driving around to the island's gas refinery to get your 10kg bottle refilled - oh and please come back the next day to pick it up (done that in the Canaries on another boat - lesson learnt, stick with camping gaz, which we could've had in the marina office).