Hmmm 🤔 For body type, Ryou would be most affected. He’s so used to towering over everyone that losing those extra 10 inches would be really disorienting lol. Sabine meanwhile would enjoy suddenly being enormous but she would miss her physique; she’s a vain little thing and likes how she looks.
For gender, it would be Sabine most affected. Ryou identifies as male with a sort of detached “yeah I guess this fits” attitude so he’d just carry on as usual after the initial adjustment. Sabine would be overwhelmed by any physical changes at first but she’s got her own identity pretty clear in her mind; she wouldn’t change much about her presentation in the long run. So honestly neither of them would change how they identify/present, but they would have different initial mental reactions.