"Thinking" is commonly known as "the dangerous thing", but. If one side broke, how solid is the other? AKA might it make sense to replace both of them @ once, especially given that the mast
is down at a time & place of your choosing.
As opposed to where it'll lay, if side #2 fails due to unspotted/invisible metal fatigue...
That, said... Riggers pretty commonly have both a bunch of spare & old masts sitting around which get cannibalized for parts
, & or tubing sections. But you can also try boat
aalvagers, used gear
"Good Old Boat" magazine has a list of 2nd hand gear
Barring that, you could do some searches for DIY
fabrication how-to's. And as a last resort, call Ericson
, or have a new set custom made.
PS: Ericon's have a yacht owner's forum. So likely they have a good bit of wisdom on this too. That, plus, you may get lucky via their classifieds section.