Best prop for 210 Reatta Merc 225

[tbird0870]

Just bought 2005 Ranger Reatta 210 with Merc Optimax 225.  It has 23 pitch 5 blade.  Only been on the water with boat empty - basically no gear.  Prop seems to cavitate at high RPM's almost as if motor is outpowering the prop.  Ranger suggests 23 pitch regardless of 3, 4, or 5 blade.  Mercury suggests 25 pitch 5 blade.  Confused!!!!