First welcome to the collective Ted.

That beam is very well supported. I was wondering in the first pic what was keeping it from bowing in the middle. Your drawing depicts nicely how it was done.
Now a bit of a saftey question. You don't work under the vehicle with it just suspended from the chain right? You do put supports up under the front end in case the chain or hoist gives out? I know your showing the strength of your beam construction here. I'm just hoping nobody thinks they can work under a vehicle just suspended by what you show.
Thanks for the nice pictures and the time you've taken to show us your setup. Hope to see more pics of your shop.
Regards,
Bernd