Bracing thickness

I am building my second instrument a tenor co-op ukulele. My LMI plan calls for braces in the neighborhood of 5/16" thick for the transverse braces on the top, north and south of the sound hole. I hear a lot about over bracing, etc. Wondering what you folks shoot for or would target for an instrument that has Koa top sides and back?

Those two braces are there to keep the instrument from colapsing at the sound hole. Unless you go way over the top they are not the ones that are "over braced". The height has more effect on over bracing tha the width does. Search the cube rule for more info.

It's the fan braces and bridge patch that you need to be more concerned about when it comes to over or under bracing. The only way you'll get a feel for what's appropriate is building lots and lots of instruments.

5 or 6mm wide fan braces