RE: Welcome to Club SAITO !
The Graupner will load that engine up, compared to the MA. I found the graupner 14x7x3 was too much prop for my Saito 125. Static RPM at 600 ft elevation was no more than 8200-8400, if I remember correctly. I think there was somewhere around 1000 RPM difference.
I ended up using the MA 14x9x3 and it appears to be the perfect 3-bladed prop for the Saito 125.
I know a fellow that uses the MA 13x8 3-bladed prop on this Saito 100 and is happy.