After some advice re the old truss rod chestnut discussion. Im a non professional but avid restorer of very broken old guitars.
Im restoring my second Couesnon GJ guitar. This time a chorus model. Had pin bridge fixed! 3ply top and back Honduras mahogany (?) solid walnut sides and neck. My usual approach is to fit a 2 way truss rod plus two carbon rods which works fine. I like relatively low action for playing so the ability to fine tune is helpful.
However i thought id review the common consensus here before the router comes out again. The neck has the original rod in place. Mild steel bar at 0.105kg (in the photos you can see the same type which was out of my previous Couesnon resto). They dont go all the way up!
So the options as i see it are keep as original.
Remove and install a mahogany or walnut strip and have no support just wood but better sonics??
Or two way rod (0.135kg) and carbon fibre strips. The CF is very thin 1.2mm x 8mm. Very rigid in one direction so minimal wood removed to fit.
The neck currently is flat with a 5mm thick fretboard of indeterminate wood. I am planning on keeping the fretboard. A bit soft so compression fretting isnt a factor. I once compression fretted an old 30's
ebony board and it does help if you didnt want any support. Any ideas welcome.