#574670;
22 - 185 mm
#576911;
205 - 403 mm when mounted on the motor side
57 - 224 mm when mounted on the side of the blade
That is from the Festool.nl website
For the 574670 I don't see a reason why it couldn't go smaller. For the 576911 there is the obvious limit that at some point the top part will conflict with the machine and you can't put it closer. But the 574670 seems physically only limited by when you would cut it with the blade itself.