Actually there are several small frames...the "frame" around the can is actually a piece of OSB the width of the can and spans one joist bay 16". Once the I wrapped the OSB for the cans I created frames to fill in the spaces using standard practices.
Seats are in...I have to say I really like them. They shipped YRC Freight (yellow cab) Roman kept me up to date throughout the entire process and answered every question. Assembly was simple and straight forward, packing was adequate heavy duty cardboard with reinforced corners and bottom. I have not had a chance to test out every seat's motor but so far smooth and quiet.