Just also to be aware that some 777-300s still have old CW at the moment.
And very much agree with danmushman about the forward mini-cabin being a nice place to be, similar to on the AA 77Ws.

The BA 77W has 4 lavatories for 76 CWS passengers (19 seats per lavatory; SPL).
It is also my experience that some CWS passengers in the forward cabin come forward to use the F lavatory, although I don't think that is strictly allowed.
The A350 should have 3 for 56 CWS passengers (18.7 SPL), but if (as seems to be reported quite often on FT) the front one is blocked off then you are up to 28 SPL.
WTP and WT manage with 39 SPL so it obviously isn't a world-ending problem.

But as stated above the A350 is more modern with a higher cabin pressure and humidity, possibly contributing to a better overall experience.