We have a ranch with a wood fireplace in the living room. It's fantastic at heating the main living area, but the bedrooms down the hall get left in the cold.
I'm going to install insulated flexible ductwork in the attic, with a blower near the inlet (red), with outlets in each room. The initial duct will be 10", with 6" to each room.
I can either run 10" to a 3-way manifold, and take 6" runs from there. Or I can run 10" to an 8"/6" splitter, take one 6" off there, then run the 8" to a 2-way 6" splitter, and take the remaining 6" off there. The first is preferable, as I'll get more efficient use of the duct, which comes in 25' sections.
Will I see a noticeable difference in airflow one way or the other? If it matters, the lower-right bedroom is the master, and it's fine if airflow is a little less there (other 2 are kids' rooms, which we want a bit warmer).