I had an occasion to repair a 1957 brazilian rosewood D28 Martin for the daughter of Bobby Edwards, a "flash in the pan" early 60's country musician who later turned to gospel music-- If I am not mistaken,his "big" hit was "You're the reason I don't sleep at night" The repair I made involved replacing the bass side of the rim which had been "repaired" with big "glob" of bondo-- and the bridge had been "bolted on" with wood screws-- by someone who should have stuck with body work. The bondo and the damage to the top inflicted by that "repairman" decreased the value of that instrument considerably.It isn't necessary to be a "professional" to repair guitars but I would think it would be wise to practice on a lesser instrument than a fine old Brazilian rosewood Martin. I did that repair in 1985 or 1986 and I would doubt that today, that guitar would command much more than the cost of the repair I charged -- had it been repaired originally by a competent repairman and not a "butcher" it would bring several thousand dollars today.