Take the strings off, and then use a makeup mirror. You can even get a makeup mirror in without removing the strings, but it's then much harder to hold the mirror and move it to see everything. You can see much better with a bigger mirror, but you still need a light.

There are basically three types of strutting and some variations on them.

There's simple ladder strutting - struts just from side to side of the guitar. Highly unlikely on anything made in the last 20 years.

Then there's fan strutting. Usually two braces from side to side, one the neck side of the soundhole and one just behind it, plus 5 or 7 radiating from the middle of the one just behind the soundhole. Often on classical guitars. It is easy if you are not careful enough to mistake fan strutting for ladder strutting, because the fan braces almost hide behind the side-to-side onebehind the bridge. Been there, done that.

Then there's X-bracing. Typically Martin. One long brace diagonally across the lower bout of the guitar, passing about as close to the bridge as it will go, plus another long one back across the upper bout from the closest point of the first to the soundhole. These two meet the side of the soundhole furthest from the player's face, so the struts for a lefty are the mirror image of those on a righty. Then several others to make a criss-cross pattern with these, but obviously these other ones can't cross the long ones I first described.

For the JLD, the main thing is (if you look at the pix on the website) there has to be enough room to get the block onto the inside of the bridge plate.

The other thing your luthier may want to know is what if anything is broken or coming unglued, and that is harder to see!