Drag artist,
We were instructed to do the stiff nut up to only allow 1 1/2 threads showing (ie achieve locking), but crucially ensure that the scissor shackle remained loose.
When tightening the nut, it is true that the base of the bolt was thin and that holding it with a spanner was difficult until you had mastered the correct way of achieving this.
You have hinted at a valid point though, how much engineering training do SAC weapons guys get these days? Don't forget, ejection seat work used to be carried out by Junior Techs as a minimum and is now done by SAC Techs. There may be something there, but I would not like to cast doubt on the tradesmen doing the job, as I have no experience of current standards. However, this critical link would be checked on vitals by the supervisor and independents by an SNCO.