Here is how the tests worked out.
Not overly scientific but I tried my best.
I took a IO 200 gal
saltbucket and filled it with water till it was at the band just above the handle. I approximated this to be 5 gal
The first test was the pump and the 3/4" hose only. It took 41 sec to drain the bucket down to the pump intake (approx 1" off the bottom") so that equates to approx 439 GPH
assuming the capacity was correct at 5 gal
The second test I added the scwd manafold you see above. Now this is not a true test of the scwd's impedance since it also had 2 45's and 3 90* elbows to flow thru but it will give you an idea. The bucket was once again filled to the same mark.
This time it took appox 58 sec to drain the bucket down to the same level. Or assuming 5 gal
capacity of the bucket 310GPH.
This calculates out to a 30% loss of flow from the scwd and the pvc
At that flow rate the scwd cycled between sides at a rate of approx 10 sec per side. At no time was either side totally void of water flow but the flow was drasitcly more on one side than the other at any given time.