I was curious how much bracing is necessary for steel strings on a 6-string with a bolt on style of neck.
Well, it depends on if you are bracing for structural support or for tone. When it comes to support I tend to use bracing sparingly. Too much and the box just goes dead and won't resonate. However, if you are wanting to brace purely for shaping the guitars tone, which most cigar box guitar builders completely fail to do, then I suggest you start by checking out this video: http://theartoflutherie.com/shaping-guitar-tone-with-brace-profiles-luthier-quick-tips/
There are tons of other tutorials on the web that you can search for and I would also suggest that you google the bracing patterns for most popular name brand guitars. That should give you a few ideas on how to apply this technique to your cigar box lids.
I'm a big proponent for both bracing as well as sound posts for cigar box instruments. I encourage everyone to experiment with both. I think you'll be very pleased with the difference they make.