Monarda didyma 'Fireball'

I'm out in the greenhouse looking over what arrived yesterday and I have two of these. I've tidied them up a little around the bottom, removed the dead leaves and little bits of wood but should I take all the thicker parts out? What about the long stems where they've been dead headed and just left long and bare, should I cut them back to the leaves? Also, when I repot should I fill them so the compost is covering a bit more of the bottoms where it looks like I can see roots? Thanks in advance for any advice