I'm not a pro, but I think mixing radiant with hot water baseboard will not work. The baseboards will heat up a lot quicker then the radiant. I have radiant in my house and tried to run it with water heaters, didn't have much luck. RADIANT TAKES A LONG TIME TO COME UP TO TEMP. Warm floors are nice, but not a substitute for 65 degree air. There was just something about water temp this past weekend on this old house. 180 degree water on the coldest days ,and lower water temps on more moderate days.