Model positioning help

[rocky crown]

I have this slime collecting game and I currently have 2 slimes modeled and textured, their meshsizes are diffrent so I sized slime1 to a size that I like took the size to meshsize ratio and multiplied the slime2's size property by those values and managed to achieve two slimes with two diffrent meshsizes to be the same size. But when I do that slime2 spawns a little bit underground due to the spawning logic which is attached

This is the function handling slime spawning

[fiery storm]

Why not move them up until their meshes arent touching with anything?

[peak wave]

basically need to adjust the pivot position