Went by Lowes at lunch and picked up everything that was on the shopping list (derived from Smokin Gator's document he sent). To ensure airflow won't be a problem though ... I went with 3/4" pipe nipples and accessories. My thought was I would rather have 2 or 3 3/4" pipes capped and available instead of all (3) 1/2" wide open.
Given that ... does anyone have a rough idea of the size hole that needs to be drilled for a 3/4" pipe nipple?