With new wood installed (sourced from Whitworth shop), I was VERY carefully shaving away at the backboard curve and the top inner fender block to match my inner fender wells. My carpenter neighbor wandered over and said:
"You know, if you smear a little lipstick on that sheet metal before you try it for fit, youll see exactly where the interference is and where to shave that wood..." Works ALOT better than chalk.
Until the Mrs. looks in her purse, I guess. But it really made the job easier.
Good luck-
Mark TC8126
Ohio