Post possible solutions below !
Going back to #315: I see (not only) Qa3# (but also d8=Q# or Qg5#)
Whereas with #325: I see only mates in two...
Edit: Thanks LoekBergman, good points. Consequently readers, do not read my (errata).
Going back to #315: I see not only Qa3# but also d8=Q# or Qg5#
I agree about #325, but not about #315.
Qg5 is met by Qxcg5 and the pawn can not move as it is pinned.
You are right(both you and funksteph) I've put the rook in the wrong position ! lol
The correct one is on b3, so the position is like below...
A lot of queens, but only one checkmate in one
Thanks apostolis1 for the correction and for your proposals in general.
So for #328 (if you say that the rook is on b3, from white pov, the board is up side down), I see only one: Ke5#
For #329, imo a lot easier: Qg8#
Thanks to funksteph for pointing out that the board is upside down:
That shows that there are two mates possible in #329, namely Qg8# or Qb1#. :-)
Dunno if anybody did this, but 330:
I'm going to do at most 10 here.