my only method of heating this old (1750) house is with fire! i run 2 wood burners,the main burner didnt go out for 3 months, because its g2 listed i cant install double glazing or fit more insulation, the roof is fully insulated however, that was the first thing i did.
as far as tips go i think its just practice, try to use the least effort possible, let the axe do the work, the beauty of the tyre trick is you can maintain a rythym so your not hefting the axe ready to strike, its down then straight back up, try to hold the axe lightly and let your hands slide so all the energy is in the head.