Gotta admire the engineering... in the past, I've occasionally "pendulumed" a trimmer to get a curved result... so long ago I just about forgotten it as I didn't take any happy snaps.

Nowadays, technology has come to my assistance,

though they don't produce a smooth arc... and rigging up a jig would defeat the purpose... let the user get splinters in their tongues. 

If your first cut is too short... Take the second cut from the longer end... LBD