I agree. With that bore size, 3f seems excessive. 2f or Swiss 1-1/2f I think would be better.
Overall, I think you have too many things going on here to say that the thinner patched load is better.
As noted, you need to bench the gun to eliminate as much human error as possible.
Blown patches are never a good thing. You get velocity variations due to blow-by that will ruin accuracy. Also, make sure your patching is 100% cotton canvas. When you said Walmart, I immediately thought, "Uh oh".
The main thing is eliminate the human component (bench rest it) and then change ONE thing at a time. Get a patching that holds together. I use The Minute-Men untreated canvas patching in .015 or .018. Great stuff. I cannot see the sun through it before or after firing. That is my pass-fail test. Sunlight.
Once you have settled on the patching, then ladder up your powder in 5 grain increments until your groups shrink. I'd start at 60 grains with the bore size.
Once you have that charge settled, trying going up or down a ball size and see if that makes a difference. You may have to go up or down 5 grains of powder with the new ball to see if there is a sweet spot.
You have too many variables changing to draw any conclusions from your first session. Go methodically through the process and you'll find the best that gun is capable of shooting. Blown patches are not the way to get there.
Also, a terrible trigger pull is not going to help you get the most out of your gun. Maybe see if someone can clean that up a little?
I hope some of this helps. God Bless, Marc