Feels like guesswork to me. Appreciate that this doesn’t help.
When the FCTM says that the approximate flare height is 40ft, that doesn’t mean “40…” then flare, it means that you need to be pulling as you hear the 40 call. It carries a lot of energy, so you can close the thrust levers promptly at 40ft as you flare in most circumstances. If your landing technique on the 320 was to flare at 20ft with the power still on, it will not translate well to the A350. It’s very rare to hear more than one “retard” call-out at 20ft.
Absolutely nail 600ft/min over the threshold. Rate of descent has a much bigger impact on flare height than the 320 series.
We had a bit of a spate of hard landings and the guidance now seems to be to accept a bit of a float and subsequent plop onto the runway than anything special, with the knowledge that if it’s a prolonged float that you go around. Of course this brings you into tail strike territory on the -1000. Oh, and flap 3 is easier than flap full in my experience.