Slime Size and texture help

Hello Modders,

I'm trying to make a mod with different coloured slimes and im having a lot of trouble getting my slimes working. First i got the 1.15.2 slime texture and recoloured it to blue, the texture had a odd map layout so i went to the slime wiki and got the original 64 x 32 slime texture, recoloured it and it worked, but it only worked on small size slimes(width and height 0.5). Then i went on to make a big blue slime but only the hitbox would change (i verified this with F3 + B) and the visual size of the slime stayed the same as before, can i get any help on this? I'd also like to know how to make the slimes actually jump around when not attacking me, seeing that they slither around on the ground.