Butt trimming to length would be the correct way to do it unless you want the club to play even stiffer. The TT recommended final length can be ignored but the tip trimming is correct for a bore-thru head. Factory steel shafted 975s, 983s, etc were rare and I can't remember what Titleist used as a stock length but I think it was 44". The shaft is heavy enough to have a standard range swingweight even if it is 43.5".