I would also hugely appreciate a copy of this manual!
I recently bought a second hand Bs350, mostly works fine but doing a few tune ups, struggling to get it to rip straight atm. It takes a 3/4'' blade but maybe that's too big to get enough tension.
I figured out how to get to the tensioning mechanism, so please ask if of interest. It was crammed with sawdust.
The riser bar that the top guide mounts to is able to rotate, but there's a grub screw under the locking knob that presumably held something that stopped it rotating originally, a parts diagram would help.
Here's some pictures showing it's not a record bs350!