independent horizontal spacing between staves

[Mason Hock]

I have a piece in which each performer reads from a score with the other 
players' staves shrunk. I have determined that the different staff sizes are 
the cause of some very bad horizontal spacing that is especially noticeable 
when players have different simultaneous tuplets. The other parts are included 
for reference only and horizontal alignment is not important. Fixing each 
instance of bad spacing manually via scaling would quickly become, even with 
edition-engraver. It seems that the simplest solution would be

(1) make the horizontal spacing of the larger staff independent of the smaller 
staves, but retain alignment among the smaller staves,

or if this is not possible the next best thing would be

(2) make the horizontal spacing of all staves independent of each other.

I have found some old threads saying that this is not possible, but thought I 
would see if this has changed by now.

Thanks,

Mason