Carl:  Well, it's regular steel not SS$$  - I think it will last quite a while as the area is dry and it has a resonable paint job - that needs a touch up.
Installation involved - loosing the stays to unload the weight and removing the 5 bronze bolts so the bulkhead was no longer bolted to the beam then using a floor jack with lots of support on the cabin sole - jacking up the beam into it's "normal" location.  If you sight along the beams in the cabin - they should be on the same plain. 
I then had to pound it into place.
Like mentioned - much easier if the mast is off the boat....
Here is the sketch of the mast brace - it was CNC'd out of a solid chunk of steel.  Not all the corners were rounded off.
