Since it is at all trim angles your choice would be to lower the engine 1 hole or look for a prop that has more rake - basically longer sweeping blades
look at this pic and pay attention to the blade design
http://www.boatownersworld.com/Props...age_series.htm
my previous prop acted the same as yours, could not trim at all without it blowing out, although no cavatation except trying to trim it. It was a standard Merc prop similar to a Vengence - rounded blades kinda like mickey mouse ears
The Stilletto I have now is another hole higher and I can't get it blow out at all - careful on RPM, a prop like that will knock off 200/300 RPM per same size
On another note - when looking at them recently they are priced at $250 new which I thought very reasonable with prices I have seen