I have a 40'x42' four bent post and beam bank barn cica 1850. The tie beams were cut at bent B and bent C for a hay trolly. Mortise and tennons are pulling apart and the roof sags down aprox 8" in center. I plan to use allthread in four places(bents B and C at eve and lower tie heights) to stablize barn, and possibly close mortises and raise sag. My question is: will 1/2" allthread,run 42'through all posts be under sized for the job?