placement of flo-checks with buffer tank

Jim_70

We are planning on adding a buffer/storage tank for a copper tube boiler next week. (thanks Hot Rod for showing the best place for the tank). I showed where we would put one of the flo-cheks on the buffer tank return.
Also, shouldn't the boiler loop have a flo-chek so that the water will not migrate back toward the boiler when the pump for the buffer tank is running? Where would be the best place for it?
Thanks.
Jim