User blog comment:Mathmagician/Wall of Flesh Solo Guide/@comment-74.199.44.228-20120625014511/@comment-4674838-20120625020044

That's a pretty good idea. Not only does it use less blocks, but also, any lava would fall down through the holes and so it'd be safer that way. (But, the number of blocks thing isn't really an issue -- if you don't have enough blocks you can always go collect more before you build the bridge.)