No cons as far as I am concerned only benefits in regard to tilting the angle of the barrel allows more oxidation and more heat(the more extreme the tilt the more it acts like a chimney)for burning wetter wood... obviously there is a trade off you get less char but when you have a lot of material to burn it's worth it.

If you do have more wet material to burn you still need dry to get the heat up. Also stacking the wet wood upright can help as it evaporates the sap outside the barrel.

Post some pics when you get it done Ryan 👍