Yes, do the radiant floor heating. You can also get special add-ons that can heat your towels when you take a shower (HW passes through the towel holder before hitting the shower mixing valve).
Originally posted by fat eddy
I would recommend if going to the cost of a dual system tou use a radiant floor heating system uses water with no ducts then use air to air exchanger for ventilation, cooling ducting in the ceiling.Tats what high end homes are using. If you did use a dual duct system you would only need dampers in the branches not two entire duct systems wit one large damper I think that system would be an abortion.