I'm thinking of planting either Sundance or Mexican Orange in a 34 inch wide (round) x 24 inch deep galvanized tub but wanted to check here first. What do you think? Will it work and how large may it get in such a container?

I had thought to drill holes around the tub about 1 foot from base at 6 inch intervals around it. Paint the inside with ashphalt paint (to keep plant from reacting to metal) and covering this with bubble wrap (as an insulator - metal heats up) .

Why do I want to do this? Because the soil in that spot does not drain well.