How much dose one OOO buck weigh? And what is the dia? I use 2.5 grains of bullseye with a 125 gr LRN in my .38s that works really well.
I just weighed some .36cal balls I have and they where about 60gr +/- 1, Problem with them is they are only .350 dia and will prolly just bounce around going down the barrel. The lightest bullet I have found so far is a 92 gr Lyman, the One book/one caliber calls for 3 gr bullseye with that one.
I think if you found a .358 or .359 round ball it would work very well with 1 to 3 grs of bullseye or titegroup. I have found titegroup to be very good for the super light loads like this.
BTW three of these balls would weigh right at 180 grains, 3 grs of bullseye would get you around 750 FPS.