Im a little late to respond to this post but I just joined this forum. I have been shooting flintlock fowlers for years and have some experience with the trial and error of testing loads. As I was taught, you shoot what your barrel likes. That being said, it takes a while to figure out what your barrel likes. The Skychief load is pretty good but very finicky. It works best with cylinder bores. It is also critical to use the overshot cushion wad that has been heavily soaked in oil. Its not an easy load to use in the field turkey hunting.
A very simple turkey load to use in the field with choked turkey barrels is using:
80-90 grains 2F
3 card wads slightly moistened with spit. Load each card wad past the muzzle then push all 3 down over powder.
1 1/2 oz 50:50 mix of #5 and #6 lead shot
Then split a card wad in 1/2 and push down as over the shot wad.
Thats it. Easy to load in the field especially if forced to reload quickly.
I have taken more turkeys than I can remember with this load.