I'm no help in the slow-it-down department, but I've bought the bullysticks with the knots on the end and they sucked butt. The knots come undone easily if you chew down the thinnest part (i.e., only as strong as the weakest link type thing), and you end up with a bunch of C-shaped chokable pieces.

Maybe Vani is better about stuff, but they were a "swerve off the road to pull over immediately and remove from mouth" for MP!!