Below are some helpful batch commands that you can add to your trade code before you start a trade.

Important: Add these commands Above the moves.

.Scale=[1-255]

This will set the Pokemon's overall size as it's displayed in the game. The values determine how big or small the Pokemon looks.

Does not work in SWSH or BDSP. Use only the below two Batch Commands instead.
XXXS: 0
XXS: 1-30
XS: 31-60
S: 61-100
AV: 101-160
L: 161-195
XL: 196-241
XXL: 242-254
XXXL: 255

.HeightScalar=[1-255]

This will set the Pokemon's Height. The values determine the size.
XS: 0-15
S: 16-47
AV: 48-207
L: 208-239
XL: 240-255

.WeightScalar=[1-255]

This will set the Pokemon's Weight. The values determine the size.
XS: 0-15
S: 16-47
AV: 48-207
L: 208-239
XL: 240-255