Several things...
I generally dislike making changes in a healthy OL midstream. It's hell on continuity. Best possible continuity would be helpful for a rookie QB, don't you think?
But I've been generally disappointed with the results of this presently constituted OL personnel wise. All have disappointed, really.
So, in the spirit of this thread, I'll take a shot.
Keep GRob at LOT.
Move Brown to LG (his college and probably best position).
Keep Barnes at C, of course.
Move Saffold to RG. He formerly played there at a Pro Bowl level before injury.
Keep Hav at RT, of course.
This involves the minimum drastic moves and simply switches the two OG's to their respective best positions.
I'd keep a close eye on the play of both OG's, and if either disappoints, I would insert Wichmann for him in a heartbeat.
Unless this combo starts to click in the run blocking, the new HC next year wouldn't surprise me with a pick or two on the OL in the middle or late round range. See what I did there? Lol.