Thunderhawk I had was very accurate, but I sold mine when I yearned for a removable breechplug to make cleaning easier, and bought an Omega.
I have a stainless I still use and my thoughts mirror PetahW. I only consider changing for the removable breech. Haven't made the change yet. In the end it isn't all that hard to clean and with the stainless I can let it sit a few days without issues. I do recommend stainless as all the powder is corrosive.
Two pyrodex pellets and a T/C superglide
or something real similar from T/C. Been a long time since I bought them. I don't think guns are as projectile specific when using sabots.