Hello. I can help. Can I get back to you in a couple hours.
I would use a single 4x6 post on each side. You can have holes punched in the bottom flange and lag screw through the beam into the top of the post.
You should also have a stiffener on each side over the post.
Hello. I am the same person. I remember your question. You can use Doug-fir no. 2, which is pretty easy to come by.
A stiffener is a plate welded between the flanges to the flanges and the web.
You can use 3/4" lag screws, 2 at each end (4 total - one on each side of the web at each end of the beam.
Yes, that is a picture of a stiffener. The holes would be in the bottom of the beam, and only 2 at each end, not 4, but it's the right idea. 3" of thread penetration with a 2 3/4" beam gauge for the spacing. The fabricator can drill the holes and add the stiffeners. Now that I'm thinking about it, make it an end plate, that way the stiffener doesn't impede your ability to install the lag screws. Be sure to predrill the wood for the lag screws so you don't split it.
That is acceptable