How would I increase a player size?

I want to make players bigger (model + hitbox)

I've managed to make their hitboxes bigger (Taller) but for the model I have no clue how to do it

@Mixin(EntityPlayer.class)
public abstract class MixinEntityPlayer extends EntityLivingBase {

    public MixinEntityPlayer(World worldIn) {
        super(worldIn);
    }

    @Shadow
    public InventoryPlayer inventory;


    /**
     * @author xef5000
     * @reason Used for the Giant Race
     */
    @Overwrite
    protected void updateSize() {
        float f; //width
        float f1; //height

        if (true) { // need to check if player is giant or not
            if (this.isElytraFlying()) {
                f = 0.6F;
                f1 = 0.6F;
            } else if (this.isPlayerSleeping()) {
                f = 0.2F;
                f1 = 0.2F;
            } else if (this.isSneaking()) {
                f = 0.6f;
                f1 = 2.5f; //Makes hitbox 2.5 blocks tall
            } else {
                f = 0.6f;
                f1 = 2.8f; //Makes hitbox 2.8 blocks tall
            }
        } else {
            f = 0.6F;
            f1 = 1.8F;
        }

        if (f != this.width || f1 != this.height) {
            AxisAlignedBB axisalignedbb = this.getEntityBoundingBox();
            axisalignedbb = new AxisAlignedBB(axisalignedbb.minX, axisalignedbb.minY, axisalignedbb.minZ, axisalignedbb.minX + (double) f, axisalignedbb.minY + (double) f1, axisalignedbb.minZ + (double) f);

            if (!this.world.collidesWithAnyBlock(axisalignedbb)) {
                this.setSize(f, f1);
            }
        }
        net.minecraftforge.fml.common.FMLCommonHandler.instance().onPlayerPostTick((EntityPlayer) (Object) this);
    }
}

This works 100% fine

But how would I do it for the model?