I'm a little late to the party here, but I've been thinking about your props. If breaking propellers is a concern (it would be if I was in combat) I highly recommend using composite gas/glow props. You'll lose a bit of efficiency but those things are tough. I'm familiar with the propellers you bought and I think they are a good option (make sure you balance them before you mount them, I've had some come horribly out of balance) if you don't care about obstacles, but a gas/glow prop will probably hold up better in a collision.
On HobbyKing they have a brand called JXF Composite that's pretty good.