MOTM

on the 410 triple filter, i understand what the rate and depth controls do 
vis-a-vis the lfo and how it interacts with the filters but where does the 
"sweep" control fit in? what does it actually control?
why only 2 lfo`s and not go all the way and use 3 ?
( i`ve noticed that these triple vcf modules seem to have elicited some 
interest from the modular user community since i`ve seen at least three 
manufacturers that offer them for their systems.  i`ve gang patched multiple 
vcf`s before over the years but never thought of it as a single module.  is 
it interesting enough to acquire or would someone be better off with with 
multiple single vcf`s ? )
best,
dave