Rowdog. I do not know as much about Saito problems as the other guys do, but here is something to keep in mind. all I can tell you is that Xoar props pull very strong (they pull a lot of air).
I had an APC 17x8w turn 8800+ on my son's Magnum 180 4st. and the Xoar 17x8 Sport turned 8200+. a 600 RPM difference. while the Xoar 17x6 Sport turned 8600+. so I would think even if you do have a problem with your engine it just may not be that big of a problem.
what did you set your lashes at?
BTW, the Magnum is long gone and will never coming back!
Jim