How do you remove individual link tracks from the model after assembling and sagging them? I've tried, but the guide horns get in the way, and it seems to me that the only way to really do it is to make them so loose that the realism disappears...

What I did was leave drive and idler loose plus some road wheels when glue has set enough just pull off both front and rear pry up a little to get over return rollers lay on side and let dry!
probley not the right way to do it but what the hell worked for me!
This is one reason why I use Friul tracks

Here's what I have done.
On PzIII and IV's I leave the sprocket loose,and the rear idler.
I only attach the inner support roller wheel.I build the track.
after painting,I slide them all into position,and glue on the idler and Sprocket.Last,I add the outer support roller.