Sounds like you are hitting it pretty good! I went from the 915F2 16.5 to 917F2 16.5 and have not seen much, if any, difference in length or trajectory. I like the feel better and not having to dig mud out of the open grove on the bottom is way better. Since you already hit the 16.5 245, you probably should base your decision on trajectory and roll. Do you want lower flight and more roll out? if so, go with 15 degrees.

Thank you Dale V.

I am staying with the 16.5* and did just buy the 917F2.