Nope, you're most likely to scorch it if you fill flush with the rim or beyond that. No danger in underfilling as long as it's properly packed; you'll just have a shorter smoke. I underfill many times when I smoke my larger pipes (those with chambers deeper than ~35 mm).
I guess I will get to understand what suits me overtime. My main smoking slot will be when I walk our (girlfriend and my) dog before bed, other considerations in regards to that is what sort of pipe is the easiest to manage and most satisfying in this situation. How long does it take you to finish a bowl with your larger pipes?