This thread is another wall of text, looking at latest proposal, it isn't centred, ctrl looks to be in a hardish to reach place, and space appears to not be big and central. I have tried to at least scan through the posts in this thread, and sounds like a lot of well thought out and researched solutions but still the "stick with what I know" in me is questioning if I would rather keep the current Pandora layout... moving some of the keys around for symbols I can see making sense.
How do you want to implement a central space? Shove it between V and B ?
Ctrl on a shoulder button (the same one as on the Pandora) should be easy enough to reach.
A centered layout is possible, but it implies collateral damage for international layouts.