Buderus Wall Hung- circ / vlaves

Louis_5

Hello and thanks for the very informative site. Priceless!
I have installed a new heating system in my house; 3 zones high-output fin-tube BB and sized it at 150 F at 10 F outdoor temp, central New Jersey, (had to make it look nice too- tried to get it to 140 F but just didn't have the space for more BB), 3- 200' loops with 3/4" pex and am considering zone valves? I think i decided on the GB142- questions:
1. which circulator should i install for the zone valves? or should i use circ for each zone? trying to make it the most efficient.
2. As it is glycol, how do i figure the quantity of water in my system to calc. the glycol mix? how much water in each foot of 3/4 pex?
3. do i need to use a header?
4. any other suggestions or ideas would be great.

thanks