I had a double bladed axe once. And at that time, I kept both blades equally sharp. While limbing out a pine tree of dead or green branches, I would swing down and chop and follow through to raise the axe up over the other shoulder and then chop down again using the other head with this swing. As I did this I would take a step and it didn't take long to limb out a trunk.

Whatever you do, have fun doing it!