I would go for two ropes,
as sooner or later you will be moored somewhere else and
getting alonside with is much easier with two ropes - one fore,one aft
To me the first thing I want to know is which cleat on the boat do I, or my crew, have quickest access to. On my boat it would be the midship cleat (your B2 but for my boat it would be the starboard side), I use a rope from the nearest pontoon cleat, P4. This means if there are difficult conditions like a strong wind, all I need to do is get to that cleat and tie off quickly as close to the pontoon as I can. The boat is now pinned to the pontoon, the captain and crew can relax and tie the other ropes at your leisure however you like them.
think layout now kind of agreed, and not going to disagree with what's been suggested.
what I did want to say is how sensible permanent dock lines are IMO. I have always used them, shackled to the pontoon cleats, heavier than our visiting lines and perfectly adjusted to our boat, and the boat is moored up in a matter of seconds, keeps our visiting sets of warps nice and new looking for longer. But I do seem to be in the minority, always wondered why more folk don't have the same setup.
Was always jealous of your set up. Very efficient
. D19 was my old one and a nice berth that one. Good luck to youlol, well just to prove that there is always an exception to the norm Paul, as you have a new boat every year there is little point!
By the way, we have just moved berths, now on D19... which I think was your old berth. Got fed up Tulana getting covered in old antifoul when the wind pointed our way from the hoist..

We have just moved our P40 to her new permanent home berth, and I want to order some permanent dock lines.
I am unsure as to the best layout of spring lines so have created a layout below and would appreciate some advice please.
Which cleats would you have the spring lines to/from?
View attachment 69912
I would have Breast lines from B1 to P2 and B3 to P6 and Springs from B2 to P2 and B2 to P6.