whats the better fan setup

[zanzabar]

so i have a pa120.2 and an mcr220 im going to be stacking (one of the fans) 1 sanace @ 2k rpm and 1 25mm spacer of a fan housing and want to know whats better, out of the 2 ways i can do it, -> pa120.2->spacer->san ace->mcr220 or -> pa120.2->sanace->spacer->mcr220

in thinking the one with the fan then spacer