The drag increase using 40 compared to 30 means the thrust needs to be pulled back a little slower.
The drag is about the same as with ailerons drag during a 30 kts crosswind.
Flare height slightly lower than flaps 30 for same conditions due to lower Speed.
Dont keep thrust in until too low before chopping it off, as many do,as it is not IF but when you will bounce it.
Landing is a visual maneuver,aim for aiming point until you see the runway rise then shift vision further while increasing pitch and reducing thrust.
If by the time your thrust is idle and you have not touched,release gently elevator force and the aircraft will settle.
Keeping thrust too high too long reduces or even cancels elevator control/feel.
Happy landings