It's funny that you mention the sizing and over loading.
I have been in touch with the manufacturer about this exact situation.
They have been very helpful, but they have asked me to return it to England or AB Marine so it can be re-pitched for 120 GBP's, plus shipping.
The rep in England "felt" that it would run light given my engine/gearbox combo. A Yanmar 3GM30F/2.21:1 gearbox in a C&C 32.
There website recommends this prop with this combination so, go figure.
They do seem to be very well built. Large bosses and bearings, some very well done machining and a over-all simple design. It just has so many moving parts when compared to a folding or fix blade prop.
I am curious as to why you would not chose one, Maine Sail?