Well I've hunted the Coyote Cong quite a bit, but the only BP rifle I've got one with is one of my .58"s. (rifled muskets) Coyote hunting would be a blast with a flinter...they are so sly and jumpy, wonder if some of them will "jump the flash"???
On calling, I usually just use a small tape recorder, but the trick I've learned with the electronic calling machines is to put your machine/player/speaker at least 50 yards out. I have a four minute delay on mine, so I find a good hide, go out fifty yards and hang it in a tree, then go back and get settled in before it starts.
That way they don't focus their attention near you, it's usually on the location of the noise/machine/player. Still I try to move nothing but my eyeballs. But it's a hoot, sometimes they will come in behind you and walk right by, all intent on the player fifty yards away. You never know what direction they will come in as they will often circle around a bit. But sometimes they will just bee-line in...you never know...don't get all focused on thinking they will appear where you think they will appear. Also don't always expect to see them moving...sometimes they do just "appear", like they have been beamed down by the Enterprise or something...they just "materialize". Yes it sounds like I've been smoking crack but it's the truth.
Something I have not tried, but is supposed to be working well, is to get a small stuffed dog/puppy toy animal, and use a "puppy in distress" call. When they see the stuffed animal, they will be so focused on it that you can get away with quite a bit of movement, which may be an advantage with a flinter, depending on how fast your ignition is.
If you could find a stuffed wabbit-toy that looked halfway realistic, that should work with the wabbit distress call, but I have not heard of people doing that.
Have fun...that's my tip.
Rat