Hey Stan,
I'm assuming that your flintlock fowler is a 20ga. (most are), here's my turkey load for my Fusil de Chase, give it a test drive, I think you'll like the way it patterns.
. 85 grns. by volume of Goex 3FFFg.
. one over powder card wad.
. one fiber wad. ( I use those lubed with T/C bore butter)
. one 20ga. shot cup. ( I use 1-1/8th ounce 20ga. cushion wads with the cushion part cut off )
. 85 grns. by volume of # 5 lead shot.
. one overshot card wad.
This load gives a consistently tight pattern and shoots point of aim out to 40 yds., but is most effective at around 30 yds.
It is a 20 bore Moe. I will give that a try as one of the reasons (besides it was raining on and off) that I didn't use it on this hunt was the loads I use are not going to kill a Turkey over about 25 yards. The load I had developed uses a 1/2" lubed fiber wad and that pushes the shot I think to the point where there is a hole in the center of the pattern. It patterns so that you have a better chance of a killing hit if you aim about 8 inches to the side of the Turkey's head. Either side. The addition of the shot cup might just be the ticket. My load was 75 grs of 3 F, a card, a fiber wad lubed with olive oil, an equal volume of shot, and an over shot card. It would do fine out to 25 yards except the center was pretty light.
I recently read about another load on a muzzle loading site that patterns really well. Powder, over powder thin card, shot, over shot card, and last a lubed wad. Sounds nuts doesn't it? But several people who tried it said it patterns extremely well.
I will try your load and this other one when it quits raining. I have not seen Noah float by so it should be over soon.
Thanks for the suggestion. 
If your pattern is still a little light in the center try using #4 shot, if I'm expecting longer shots I move to #4's, #5 usually works well for me, I had the same problem with heavy loads blowing the center out of my patterns, lighter loads like 60 grns. of powder under 1ounce shot loads pattern pretty well without shot cups in my fowler, but that's too light for turkey if your shot is not perfect.
A friend of mine who lives on the Priest River in Idaho is an avid mid 1700's primitive living history buff and Hunts all his game from squirrel to elk with his flintlock fowler, he's the one who suggested the load to me and it works great in my 20 bore, I use the same load for deer, I just leave out the shot cup and shot and load a patched round ball, accuracy is dead nuts accurate.
Before using that load my fowler shot low, I had to cover the target with the muzzle to get the ball near center, with this load I shoot point of aim and it shoots clover leafs at 25 yds, and about 2" at fifty.
I think the combination of 3-F and the addition of the card wad and fiber wad gives a bit more velocity to stabilize the ball, and when using shot, the shot cup holds the load together until it's well out of the bore and helps to keep the pattern tight, It's been often noted that guns made for the old style paper shells and loaded with card and fiber wads shoot one choke tighter when shooting shells with modern plastic shot cups, it's the same with muzzle loading smooth bores.
Some folks won't use them because the say the plastic melts in the bore and leaves a residue that's hard to clean, my experience is that it doesn't happen as long as an over powder card and fiber wad are used under the shot cup.
I've since started using the plastic shot cups in my muzzle loading side by side percussion shotgun for hunting upland birds and the gun shoots like it's choked tight IMP. Cylinder, I'm pretty sure you'll like it once you try it on a patterning board.
