RE: trailing edges
Here's whay I do.
Note, the drawing shows how to mark a piece of TE stock for beveling the Hinge Line, but the routine is the same for the other end.
Lay the stock on a flat surface.
Take a straight-sided ink pen, and lay it flat next to the wood.
Slide the wood along the tip of the pen (The pen doesn't need to be centered on the wood, just close)
Flip the wood over, and repeat on the other side,
Now you have two lines. Sand each side down to the line and you're even,