This is also a difficult question to answer because some parameters are quite personal.
As a rule, smaller calibers develop less energy, and the air consumption (cm3 per Joule of energy) is higher than with larger calibers.
This also means that larger calibers can develop more energy, and the air consumption (cm3 per Joule of energy) is lower than with smaller calibers.
Smaller calibers have flatter trajectories in flight with lower energy (but with similar V0).
V0 = Muzzle velocity of the projectile.
Larger calibers have more stopping power with the same energy.
Larger calibers usually require more energy to be more accurate at longer distances, and higher powers usually have a higher Ballistic Coefficient (BC). Higher BC retains the energy at longer distances = lower deceleration = less shift from the Point of Impact (POI) in windy conditions.
To help decide which barrel to choose, you can read the complete Technical Specs made by EDgun Leshiy Store HERE.
The good news is that no matter which caliber you purchase the Leshiy 2 in, all you need to do to change the caliber, is to buy a new caliber kit which contains barrel, magazines, and suppressor. Those are all the necessary parts to make the transformation.