Here's an updated picture describing the flow



Here's the diagram I'm using as a general guide:



The main pipe coming out of the filter is 1". The loops on the roof will be 1/2". The flow is reduced when flowing up to the solar loops, of course, but still acceptable.

As for winter, I plan to leave it in place, and blow out the lines. I will be taking down the solar loops as the pipe is a little more fragile then the main system which is poly pipe.