I'm glad you enjoyed the Oboz event!
When you talk about a callus, I'm wondering if you're actually talking about a corn? The reason I ask is typically calluses aren't painful or cause issue--they vary in size and shape. A corn is a small, raised center bump that's surrounded by inflamed skin and can be tender when pressed. You can buy special corn bandages to help relieve pressure caused by a shoe if that's the case.
If the issue is being caused by a large callus pad that's somehow impacting your gait, I'd actually recommend going to see a podiatrist before you try any home treatments or make footwear adjustments, since they aren't typically supposed to be large or painful.
I'm happy to offer more ideas if you have more specifics on what you're experiencing, but a doctor's advice is best, especially if this has been a chronic issue.
Here's to happier hikes!