Do these run pretty true to advertised pitch or slightly stiff? Currently running a 25 solas 4 blade right now (came with motor and not the right prop at all) and trying to pick up 800 - 1000 rpm. Currently turning the 25 solas at 5100 and slow hole shot. Local guy has a rev 4 cheap but it's a 21p that he claims is closer to a 22 or 23.