With the way you are proposing your setup, there is no way to shut off the flow to the panels so they will likely always have water flowing through them. If that is what you want, then it is fine. A 3-way valve instead of the first TEE as shown in the original picture will allow control either way and probably cost the less than two two way valves.

Also, it looks like you have removed the vacuum release valve which means you will need to drain the panels manually in the winter and that they will contain water when the pump is off.

As for the pump, I agree with Carl. I am using a 1/2 HP to run solar on a 25' roof so you really don't need much of a pump to run solar. With only 4' rise, you could probably get away with the pump you have or at least try it before getting a new pump.