Ditto what TerraNova just said. I have used a fair amount of tropical hardwoods on fancy projects, for other people. They generally request these materials because they had access, because they look pretty (at first), and because no one else had seemed to ever use them for outdoor or otherwise exposed
service.
If you are still considering it, then my experience has been to seal the wood with West System
epoxy with 207 Special Clear Hardener, several coats, followed by several coats of a clear linear
polyurethane 2-part sealer/varnish. And expect to have to redo the finish every couple years. Think rolling big rocks uphill for the rest of your life. Then leave it as one of those fantasies you want to retain in your
head for eternity.
Here's a pic of a
project I did with Honduran mahogany and African rosewood: