X3: Can the fader "throw" be adjusted...

Because I use the Mackie Control I have full 100 mm throw and it is very precise. 
 
However, try Offset mode to get more throw.

I guess I was thinking you were asking for the faders to be more sensitive, as in you have to move them less to get more of a volume change (and am still not sure... because derpy me doesn't know what you mean by granular)... BUT if you want them to be more accurate (as in you have to move the fader further to affect a volume change) then as John said try Offset mode.
 
One thing I learned in my last round of learning how to mix is that to get more accuracy you should do a rough mix and then enable offset on the faders so you are starting at 0db and you can be more accurate.
 
Sorry... I may not be explaining this properly (and you may already know this) but do this...
 
Set your DRY mix so that all your tracks are registering at around -12 to -16 dB (or even lower if you are going to be piling on heavy gain effects) so your master bus has plenty of headroom while at the same time trying to get the levels to sound about where you want them to be.
 
Then apply offset mode to the faders.
 
Now you will not have to move the faders as far to do your more precise mixing.
 
You do this because a) once you start moving the faders further down or up from their starting point you lose resolution so you cannot be as precise and b) it's a lot cleaner to look at/deal with faders that are all more or less in a straight line when you start your mix.
 
I think I picked that one up from the Groove3 Mixing Rock tutorial even though he was using Pro Tools.
 
Just remember that you have set the faders up to Offset Mode and be aware of the key bindings that enable/disable Offset because it's easy to disable it and get totally screwed up. In fact I've seen it mentioned many time here to either disable the Offset keybinding or change it to something off on some obscure area of your QWERTY keyboard to avoid accidentally triggering it.
 
I hope that makes sense and is relevant to what you are asking. Cheers.
 
Oh and for ultra fine adjustments you could always just manually input your dB level. eg: get it close to where you want, look at the dB level and just punch in a new number higher/lower as need be.

One thing I like to do when I'm automating a vocal track is to hold shift when I'm dragging the faders with the mouse. Instead of the faders moving by about .5 dB they change it .1 dB. This works for most controls.