Yes the top of the stove is not much bigger than the 2B but that large back burner on the 3B has to be a boon.
I've always found 3 burner stoves questionable. Even with two pans going, there's not much room on the cooktop. Thanks to this discussion, I learned that there is a bigger burner for bigger "fry(!)".
Given the size of your boat, only YOU can decide how you want to use it, with the options presented.
Some folks can actually leanr to use their pressurized stoves. We did on our C22. When we bought our C25, it had one that was knackered. We replaced it with a 2B Origo, non-gimballed. No way one could cook on a small boat, and if we needed to I would have bought one of those bulkhead mounted gimballed units for making hot water. I opted for a thermos!!!
We have CNG now, in San Francisco. Supply of CNG is very close to our marina, hence, no worries about backup, plus we have two CNG tanks aboard. Backup is my middle name, until we bought an empty CNG tank and making coffee that morning became impossible.
No one mentioned this: CNG tanks are BIG and HEAVY, like oxygen tanks in hospitals, only painted white, not green. CNG would NOT be an option on your boat, even if you were my dockmate with easy access to replacement tanks.
Forget CNG and most folks know the issues about heavier and lighter than air.
Do you like scones? Then get an oven and do what Brian has done - great job there, looks and works great.
A drop-in ORIGO would work wonders for your peace-of-mind.
A propane system would be another choice, with its demonstrated additional components.
Other than visiting other countries (i.e., Canada and Mexico - west coast bias since my boat is here!
), I'll keep my CNG (it works for us), then would go to alcohol non-pressurized (could still get an oven from Origo), then propane, LPG or whatever they're calling it this week - cooking fuel?).
Your boat, your choice.