Don't know the answer to your question. And you may be close to the mark with 8-10 m. I think we need to strengthen elsewhere as a priority.
Definitely a striker, a mid-field playmaker with mobility and aggression (maybe that's 2 players ?). Next would be a mobile centre back and finally a #1 /cover for full-back, wing-back (preferably both sides - one with versatility would be ok). Unless we get a new owner, with a tendency for reckless abandon, I doubt we'll be spending more than 30-35 m on new recruits.
Thus, in my opinion, shelling out on an 8-10 m 'keeper is unlikely and unwise, given we have a couple of competent 'keepers to vie for #1 already.