Also , since I'm still new to all this, how tight /much torque should the nipple be in the drum ? Just snug or cranked down ?
I only barely snug the nipple and keep it rather loose because the drum is softer steel and you don't want to bugger up where it seats which is easy to do.
I recommend to keep it loose if you want the drum and threads to last a lifetime.
The nipple has plenty of threads to not need to worry about it backing out.
I recommend the same for the clean out screw.
Keep the threads of the clean-out screw clean and lubed, and don't let it rust in place or gall.
Both sets of threads get fouled easily.
Another reason to leave them "loose" is for when you need to dribble powder into the drum after you dry ball or have multiple misfires.
There's no need to make it more difficult to remove either of them in the field or at the range in order to coax a few grains of powder into the drum.
One problem with having caps fit too snug is that it becomes very difficult to take an unfired cap back off.
You could end up needing to scrap it off with a knife blade.
If you don't have a knife handy then you'll need a piece of plastic such as a credit card, or you'll be hunting for a twig to help scrap it off the cone.
Sometimes it's easier to just pinch them.
Sure, it's worth trying another nipple to see if it fits better.
But if you end up buying tighter fitting caps then you may end up switching back to the old nipple, so don't lose it.