A lot depends upon the type of wood you're trying to bust...a narrow wedge, while requiring less power, will sometimes pinch and hang up, especially in stringy wood. A fatter wedge takes more oomph, but placing the "kickers" further back on the wedge will give the best combination...a thinner wedge to start the split, then a wider section to open the log up.
A narrow wedge is not a deal breaker.....I have welded heavy angle iron kickers to many thin wedges over the years.
