Second that:
Russ L said
"If it's simple like a shroud tang or spreader base I suggest you consider a compression tube. Much easier to make and prevents overtightening. Simple S/S pipe has worked for me in the past.
If you require load spreading, consider aluminum doubler plates fastened permenantly and the compression tube.
If the bushing can stay put (not usually removed) I would go with S/S same as the bolt and TefGel the bolt to make the bolt much easier to remove years later. "
plates fastened with machine screws
Do you have a Kenyon Spar Douglas ?