I hope the airframe is clean enough to make use of the pitch. This is an E3 thinned a bit and slightly down in dia to about 4.1". I will test and trim with a FG combat prop to slow things down a bit.
The FG combat prop will give you by far the least amount of time to react to an out of trim / balance condition from launch. Your plane will be doing 90 mph before it gets 20 feet from your hand..[[well, maybe just 88 or 89 mph].
I used to use Cox 6 x 4s cut down to 4.2 or so before I discovered the APC 4.2 x 4. The Cox prop worked OK and was durable for "trim out duty".