Took your advice from your responses to yesterdays question.
22"x8" is a standard rectangular size I could get at a supplier or on-line. I've currently got 6 flex-ducts going to the room registers. It's a one-zone system. No branches. I think I could do the gig myself, but I am unsure of sizing the duct.Currently, the trunk size becomes smaller as you travel the length of the trunk. There are three places where a reducer fitting is in place. The quote from the sheet metal company only stated 22" x 8". Not knowing anything about duct sizing, how would I know what size to get and where to put the reducer fittings? Otherwise, it looks like a job I could do using standard prefabricated parts.
Thanks again for your consideration.