Stacking Rearrangement

I’ve just ordered my next part in optimising interconnects and I plan on improving my system stacking order as well.  Presently it is, going down...

Left: 552, space,HDX, nDAC, 500

Right: nVi, space, 552PS, 555PS, 500PS

I am going to move the space from the braun side and put it either beneath the HDX or beneath the nDAC. As it is a big operation I can’t go testing and comparing.  I’d be grateful for advice! What do you recommend:

Putting the space beneath the HDX or putting the space beneath the nDAC??

Many thanks