Considering some of the wild architectual drawings, that are built into houses, it's a wonder they hand any place at all to install the indoor unit. Some of these homes really make you earn your money. All an AC systems is, to an architect, is a square box with an X in it. Their so ingross with designing these temple to their glory, they don't even consider the room necessary for the AC system and the ducting alike. And!, the builders don't giva$!*#t either. It's all about the bottom line! I tell them all the time that AC is not like running wire for electrical or piping for plumbing. We need a little more room for ducting. Like Mark Beiser, I too, don't like using wyes or transitions if possible. Since I balance all of my new installs, it's a lot easier and better for the customer in the end. Of course there are those that just want cool air and I do my best with wyes and transitions to deliver the proper air flow to the rooms according to the manual J. I would have installed another supply plenum on the end of the first, or aleast cut one in half and installed it to be able to stagger and offset the start callors. You have to have that pressure build up for the system to operate correctly. But then again it's the bottom line with the builders. It is so competitive here in Texas, in the AC business, that the cost of an extra plenum to do the job right, could or will loose you the job. Some of the companies are using alien/illegal workers to install the roughins and then use their techs to do all of the operational procedures. I see it every day, a truck load of illegals with a load of ducting and materials going down the road. This is not excuse, just the nature of the beast, at least for now.