Don't apologize, you are here to learn aren't you?
Thanks for the link. What makes the waveline so superior to the Tunze, just curious, I read some articles but it doesn't mention much about the new technology that you mentioned, the soft start feature and variable speed are nice features!
Nothing new about a variable speed DC motor. Is easy to do, a packaged variable speed AC motor (with built in VFD) would be interesting to run. It is a relatively new pump. And looking at the specs, you can see it knocks the snot out of the old standbys.

You want to go much higher than this tank, you run out of options rather quickly, other than the larger reeflos such as, the Barracuda, Hammerhead, and beyond.
I will still probably use a small separate pump to run water through the reactors and into the Refugium, I just think that will be easier, and it only needs to be a small pump to filter through the reactors and sump.
I am trying to make it simple for you, and you want to keep making it more complicated. :celeb2:
This is really simple.
What you have to remember though, is I recommend against splitting the return like this. This was done for someone that just would not let it go.
To run your reactors, you tap the branch off the return line. On the other hand, reactors are a "down the road" addition to the system. They are a waste of time on a new system. For one, you have no idea what you are going to need. Sure, they are recommended all the time; that does not make them necessary, or in some cases--even desirable. It is important to learn how to manage a system, without such crutches. That way, when things go rotten on you, you know how to deal with it. You won't panic, start a thread, and have everyone tell you how to do it, every way but the right way. This happens a great deal with calcium reactors; GFO can casue you problems as well.
My only concern with that is that some of the water will go back to the DT without going through the reactors, is that something I should be concerned about?
Putting it bluntly: Who cares?

Not me--nor should anyone else be concerned about it. No one should have a concern about slowing the flow rate through the sump down, so all the water will go through the skimmer, either. For some unknown reason, that is a great debate starter. That won't happen, no matter what you do, anyway.
What occurs is cumulative, not one pass. So you need not be concerned about the percentage of water flow through here or there--the important number is what is flowing to and from the DT.
I've looked on the BRS site, can't find anything mentioning optimal flow, think 600GPH split between 2 reactors should be adequate, right?
Maybe you should start looking somewhere other than the BRS site then. I can't help you here, it depends on the reactor itself, and the type of media. You are likely to get as many different answers as there are people running them.