Why don't ya just do like what our fore-fathers used to do - Chew on a piece of tree bark ;-]
Sorry, man... Nothing personal. That one just kinda seeped out
But yeah - I hear ya. I've observed the holes are either too small or too big. It's like the toothbrush holder manufactures can't keep up with the marketing gurus at the toothbrush manufacturing companies. Guess folks will just have to take measurements of their toothbrushes before re-modeling their bathrooms.
As a side, it's been discussed in health journals that keeping your toothbrush out of sight is more sanitary and healthy... For a few reasons.