This is not one of my better plants.. But I like the berries and the trunk is interesting... The branches need some work, and I'm not convinced by my choice of pot, but I didn't have anything that fit and was remotely suitable at the time. Any suggestions about the pot?

Well, your Pyracantha looks healthy and full of berries!
Congrats.
I would go for a glazed in opposite color from the berries (deep dark blue) or a very light yellow to complement the berries.
It's for the berries that we grow Firethorns, isn't it?
Or for the nasty thorns?

I would go oval maybe.

With our garden wie seldem have problems with tree health.. Except leaf burn on our maple trees... Because of too much sun.

I agree glazed and I like the idea of contrast.

The birds are also happy with the berries... Half of them are gone already.

I suppose I should add the flowers picture from this spring.