I've been building up a collection of notes from various sources on general rules of thumb for chamber dimensions and tobacco choice. Most of it has been taken from
A Passion For Pipes with some added from various episodes of the pipesmagazine radio show:
* The robustness and complexity of English blends, for example, are underscored when they are smoked in a pot or a Prince. Both shapes have chamber geometries that are, for all intents and purposes square. Their diameter is approximately the same dimension as their height.
* English smoke best in a square bowl - where depth and diameter are relatively equal
* While conical chambers may have gone out of fashion (this is my impression), they are remarkable when smoking folded-and-stuffed Balkan-style flakes. I find that conical chambers exaggerate flavor development as the tobacco burn progresses toward the bowl bottom.
* a pipe shape that is likely to be a fine Virginias smoker, I think of the billiard. The billiard’s chamber configuration emphasizes the sweet aspects of mature red Virginias
* Orientals and latakia are best in a bowl with a large circumference
* Pots and princes are my shapes of choice for English and Balkan blends
* For me nothing beats a 3/4" bore 1 1/2" deep group 4 pipe for softer continental and McClelland Va flakes. This size or a slightly larger group 5 is great for Va ribbons. For the dense Samuel Gawith flakes I like a slightly smaller group 3.
* Your draw has a greater effect on a smaller diameter chamber versus a wider chamber
* Milder straight virginias and vaper's are best suited for narrow chambers
* more robust blends, or more complex blends, are brought out better in wider bowls
* they smoke cooler and have less of a draw effect
* plus you wont miss a certain type of flake in a more complex blend
* If a tobacco is too mild, try it in a pipe with a smaller diameter chamber - this may bring out more flavour