I’ll start by saying what ever works best for you.
My 52 is above the NDS because I have a TT above 52 separated by a medium length leg in the Fraim. So I think your space between them is a good idea. Others may take a different view.
Because I decided that the signal stuff would be sufficiently far from the PSUs by raising them above them. Also, cable dressing makes more sense to me this way. And I don’t really subscribe to the brains vs brawn thing. I don’t disagree with the application of it but it just leads to other compromises.
Just to avoid confusion, my own system is as follows:
Left stack
LP12
NAC52 (Med shelf)
NAC52PS
SUPERCAP (For prefix)
Right stack
NDS (Med shelf)
CD555PS
NAP135
NAP135
It is sounding better than ever since a recent rebuild to accommodate the Supercap.
After suggestions on another thread I have NDS top, 252 next, Melco bottom. The PSUs and 250DR are in another stack.
My feeling was NDS above 252 possibly more detailed but I’m still not really sure if the overall sound is better. I may try the 252 on top again.
I have the standard fraim supports.