I've actually been wondering about that for years. Over here we teach our main base to be right underneath the flyer (for one legged stunts), while the secondary base needs to get as close to the main as possible (chest touching).
For two legged stunts it's chests together an every base underneath the respective foot of the flyer.
I've rarely ever seen that in most allstar teams. Bases seem to share the weight and base more like a triangle with the flyer standing on the tip (sorry difficult to describe). I've always asked myself wether it's supposed to be like that and just a different technique.
Any insights?