New house with combo Geo unit. Forced air is priority. The home has aprox 1800 sq ft of infloor heating. Another plumber has used a 60 gal indirect electric boost hwt for slab heat. The Geo heats the 60 gals. All slab heating relies on heat transfer from indirect coil. House has 4 zones each with 6 gpm pumps. To me you should use a buffer tank. Will this other system work?