Being in the 'plumbing' business, I'd like to throw a few things out there.
First off, I would love to have the resources to make a full scale mockup of both the standard injection system, and of the electronic systems with returns, and have Don Rivera do a flow and suction test. We then would have hard data, but only of the mockup. That data may not translate to all of us.
With the wide variety of accessories available to the builder, it makes developing and plumbing these packages tougher. Think about it.
WE used to ask if it was carbed, or injected, and what selector valve is used.
Now, we ask the same, but add, inverted fuel, and if so, left or right, or both, what boost pump and filter package, and if a console is used. OR is the selector valve in the stock location?
If all the RV7s were equipped the same it wouldnt matter. If all the RV8's were the same it wouldnt matter. The problem is, if you use something that isnt in the plans, or deviates from the plans, it becomes a different scenario to solve. The RV7/9 cabins with the duplex valves are a tough project. We dont have the ONLY solution, I'm quite certain there are others. But, for the constraints we were given, we worked through a bunch of options and came up with one that was relatively simple, was reliable, and wouldnt break the budget, and would solve the problem for MOST builders. Not all, but most. Its time consuming to do a custom install for each builder. Literally, you would have to be onsite to do most of the work. That isnt feasible, we tried it. Some of you know what I'm talking about.
Its experimental aviation, not production. I would almost bet that if you took all the 'like' models of RV's at Oshkosh, none would be exactly alike. Unlike a Cirrus, Piper, Cessna, Beech, etc. And I guess thats why we like it.
So---I personally think its fine to put on the forum an idea and get some opinions. I know I have, both good and bad. But, I've learned from both, and have tried to apply that to what we do. None of us knows it all, there are just too many systems and variables now. But, somewhere, someone has run across what you are trying to do, and has an opinion on it.