Agree with T*O*F....
I've found that 90% of engraving is being able to sharpen, and re sharpen gravers. I also have learned that doing this with a jig is soooo much easier than doing it "by eye", or with something home made. Because of this experience, I tend to lean towards the 3/32", and use Lindsay templates to sharpen. Obviously, there's cost involved, so you'd have to weigh that consideration. Either size will work for what your wanting to do. Just my two cents on the sharpening aspect. Some people like the experience of sharpening "by eye", or with some sort of home made jig, and do very well with it. I'm not one of those people, lol..., and found the templates to be far less aggravating.
Ed