The keyboard shortcuts for Insert Entry (^ =) and Delete Entry (^ ⌫) are impossible to enter with one hand. Please either change these shortcuts to something a bit less sadistic or provide an option to allow users to change keyboard shortcuts.
Just as a suggestion, you could always enable "sticky keys" on OS X which would allow you to hit the ctrl key first and then the = or del key.
And, if you are not on a laptop, extended keyboards by Apple and others have the ctrl on both sides.
Thanks for your suggestions. Unfortunately, I am on a laptop... Sticky keys is a good idea, except that this is the only app I own where it would be useful. I think allowing users to change shortcuts is a better overall solution.