I'm rigging up open storage and panel rads this year and am going with nofossils diagram from the primary secondary sticky. My biggest question (among others) is whether the zone valve on the storage loop should be large or if 3/4 would be ok. I'm thinking flow rate through storage shouldn't be too huge an issue? I've got a bunch of 3/4 zone valves just kicking around so am hoping I don't need to pony a hundred or so for a 1-1/4 zone valve. I'll have a 3/4 zone valve on each of 6 home run zones going out to rads.