I'll assume the 4150 is driving mids/highs whereas the 2100 is serving substage duty?
Set the filtering to high-pass for the 4150 to around 80Hz or so.
Set the filtering to low-pass for the 2100 to around the same value ~ 80Hz.
See how that sounds to you and then tweak each one way or the other in smallish increments until you get the sound you're after (or at least a close approximation to it)
No - incorrect crossover settings aren't going to cause the amp to go into clipping.
However, if you send inappropriate frequencies to the drivers your amplifying (such as sending a 60Hz bass note to a tweeter for example) you can bottom out the driver in question and damage it that way...