I started searching for a kit about a year ago and found this set of DDrum AMX shells:
14x6.5 snare
12x8 tom
16x16 floor
24x22 kick
and just started adding to it.
The placement was influenced by three things: Mike Mangini, Gary Chester, and Derek Roddy.
Gary Chester advocated a set-up in his legendary book "New Breed" called territorial rights. As a natural lefty being taught on a right handed kit, it was kind of an obvious step to give this type of set-up a try and it definitely worked pretty well for me.