Size does not get much attention due to it not mattering in gameplay until ZA. There is excellent documentation on size across different games, but there is one aspect that may need some new evaluation.
If you move a XXS or XXL Pokémon from Go to Home, it gets the 0 or 255 Height, the limit on either end. SV acknowledges this and appraisal will grant the Mini or Jumbo Mark. I have multiple boxes of size-marked mons using the Go > Home > SV flow.
Home will show sizing based on last game: height measurement for PLA (feet or meters), a size classification (XS, S, M, L, XL) for ZA, and nothing for other games. Aside from one curiosity Anubis dug into, there hasnt been much ZA size research. And now that it is recently Home-compatible, the behavior seems different? I have had some Go min/max Pokémon stored in Home, ones that are not available in SV.
Today I moved five of my stored batch into ZA... and they got seemingly random size classifications
M: Electrike, Vanillite
L: Melmetal
XL: Absol, Buneary
I unfortunately do not have which were originally XXS or XXL recorded (moved to Home in '23/'24). Visual inspection wasn't immediately clear. There is no appraiser in ZA like there is in SV.
I plan to try and gather more information from my limited end (I do not have a way to get anything to PKHeX currently). Café visit screenshots should give me better visual comparisons. I have at least a box more in Home, but want to understand better before I move much more. Especially when moving to ZA means blocked from prior games (which i don't think was ever explained why, last I knew). But if anyone has recommendations or assistance, it would be appreciated. I mainly got curious after seeing Champions has visual size differences (and size marks in the ranch gacha too).