[Zeke]

Typically there would be 3 studs either side of the header, 2 jacks and a king. Since the 6 x 6 is still going to need jacks unless it is notched, I don't particularly see the point. A man door and a window plus the roll up pretty much calls for one continuous header across all the openings with the man door and window framed down to their proposed height.

But there are more ways to skin this cat so you could set 3 individual headers but you're gonna need a lot of studs in that span. I'd just go with what uses the least amount of lumber and also remembering that larger lumber does twist, etc. more than 3+ studs nailed together and strapped.

I have to admit that a glue lam above with 6 x posts would be hell for stout. Might as well put a hook or eye up there for a chain fall when you need to lift something.

(edit) I kinda rambled a bit there. A continuous header with 6 x 6 posts set in post hardware appropriate for top and bottom, either side of the big door, probably aren't going anywhere and somewhat simplifies the framing. My limited experience in areas that use a lot of southern yellow pine tells me large dimensional lumber is not common. The quality of a 6 x 6 is important. Out here where we use fir the big stuff is crap anymore.