Wait a minute .. do you mean your problem is that you are using spherical picking mode on your sprites, which is what you need, but the picking radius doesn't change automatically when you are scaling the sprites ?
Then you could keep using sprites and simply write a function that scales the sprite and sets the radius at the same time.
Or did you mean that you need pickmode 2, but you can't get it to work with sprites ? That was what I understood, so that is why I suggested using a mesh instead. If so, how are you using the sprites ? You could then write functions that are more or less compatible with the original sprite functions and use Ctrl+R to replace them.
Then you could keep using sprites and simply write a function that scales the sprite and sets the radius at the same time.
Or did you mean that you need pickmode 2, but you can't get it to work with sprites ? That was what I understood, so that is why I suggested using a mesh instead. If so, how are you using the sprites ? You could then write functions that are more or less compatible with the original sprite functions and use Ctrl+R to replace them.