If you want to do the K14 historicly accurate then an 80mil average star reticle or circle and pipper will do. In the P51D and P47M, N, and D40, you will note the K14 gyro sight has two projector lenses.
Left Hand Lense: The left hand was for bore sighting, bombing, and if wanted, for gunnery a fixed circle and dot instead of the six sided star.
Right Hand Lense: The right hand was for the six pointed gyro star and pipper. It could be locked in place as a fixed reticle.
In our game HiTech has not included a functioning Gyro program for the K14 as IL2 has included. So your six pointed star reticle is in fixed mode. But you can vary the size for wingspan. The original K14 in 256x256 is about 106mil and fits the max wingspan projection in the games K14 reflector plate. Thats about a 109 wingspan @100 yards. I'm using an 80mil star which is a 109 at 200 yards. You can substitute the original N9 ring and dot for the right hand reticle. Just remember to adjust your cockpit forward view center line to place the dot for the star reticle centered over the right hand lens or the dot for the circle reticle over the left hand lense. Like in the P47D-11.
Below is a link to a K14/GGS article showing this.
http://forum.axishistory.com/viewtopic.php?p=160621