Radiant heat manifold size

Geo_4

I'm installing a 1/2" pex stapleup system in 2- 600sqft areas, each with their own zone. I'm running a 1" feed and return off my primary manifold to that area. I was going to use a common system pump with z-valves for each zone. Each zone will be heating 600sqft, new construction. Can I use a 3/4" manifold out across the basement for my supply and return for each zone or will I need to use 1"? The 3/4 would be cheaper but I want to do it right. Any help would be great. Thx