Barrels of fun

Went to the garden centre today looking for an outsize pot for my pink willow. There were lots of these barrels and although I decided it was too cold and I just didn't have the strength to lug one home, I'm definitely going back to get one in a couple of weeks.
The willow is a really thirsty plant so no holes in the bottom is good, but a lovely man showed me exactly where to drill holes in the side to stop the pot flooding in winter and told me to go for John Innes no. 3 so it won't dry out too fast. Any additional advice welcome!
Because they're barrels sawn in half and not smooth pottery, of course they wouldn't stand in neat lines. I thought this jumble was really fun..