The tooth pitch is determined by what material you want to cut. The height/thickness of the blade is determined by the length of the blade, tension, and whether it used for straight cuts (horizontal bandsaw) or free cutting (vertical bandsaw). Horizontal bandsaws will typically have a much taller blade, in the neighborhood of 3/4"-1-1/4" so that you can run really high tension and prevent the blade from deflecting. Vertical bandsaw blade height is generally dictated by how sharp of a radius you want to cut. Here's a nice clean chart from Dakin-Flathers:
View attachment 382237
When selecting tooth pitch, you want to always have a tooth engaged in the cut so it doesn't bounce between teeth. For example, 8 teeth per inch (tpi) is 1/8" tooth to tooth, so you really should only use it with 1/4" and thicker (2 teeth engaged at all times), and never use it with 1/8" or less because it will break off teeth, break the band, or pop off the rollers (or all 3 at the same time).
If you have too many teeth engaged, it takes more pressure to cut, which is also not efficient and does not clear chips properly. Each tooth makes only 1 cut as it swipes across the material being cut, so you want to make sure it can pass all the way across the material cleanly without overloading. Once that chip fills the gullet (space between the teeth), the tip can no longer engage the material and simply floats across, basically cutting nothing. With a 24tpi blade in 1/4" steel, you have 5-6 teeth engaged at all times, and they are much smaller teeth, so they cannot cut efficiently.
10 gauge steel is approximately 0.140", and 1/4" is 0.250", so to cut that material, you want a blade with the coarsest tooth count possible for the thinner material, and not more than about 3 teeth engaged in the thicker material. 8tpi (0.125" between teeth) would technically work, but will be way too rough on the 10ga because you will feel the teeth dip in and out at each transition. 10tpi would give you an average of 1.4 teeth engaged in the 10ga (0.140" thick divided by 1/10tpi=0.100" between teeth)and 2.5 teeth engaged in the 1/4". 12tpi would give you an average of 1.7 teeth engaged in the 10ga (0.140" thick divided by 1/12tpi=0.083" between teeth), and 3 teeth engaged in the 1/4". You could also do a 14tpi to be smoother on the 10ga, but then it will take more force and cut much slower on the 1/4". I'd recommend a 12tpi blade, or a 10/12, 10/14, or 12/14 variable pitch blade.
Also, spend the extra $$ on a bi-metal blade. They come with teeth that are heat treated and of a harder material, so they will last longer and cut better. Don't cheap out on it. I'm a big fan of Lenox blades, but any bi-metal blade from a name brand such as Lenox, Dakin, Starrett, Morse, etc will be just fine. I buy most of mine on ebay because you can save a ton buying new old stock stuff from supply houses. Post up what saw you have, or the blade length and height, and I can help you find something.
