I've included this copy of the party schedule here in case you want to develop your own party and need a sense of how things need to flow.
In this overview you'll see the steps needed and get a sense for how many volunteers you might need to have helping (one to cut threads before you get to the point where you need threads for instance; and cutting threads in advance and bringing them to the meeting typically doesn't work because they get all tangled). The limiting factor of this type of party is how fast your copier runs. Typically we get through the sketching part and the layout phase pretty quickly. Things bunch up at the copier. (We have always had a great copier operator who is unflappable.) Once you get through that bottleneck everything is smooth sailing.
I highly recommend that you have DRILLING stations to drill the holes for sewing (there are two sets of holes so people have to return to the drilling station twice). For 35 people having at least 5 drilling stations is a good idea. A person who is comfortable with drilling holes can quickly move through 7 books, accurately and cleanly, one after the other. And this means the group as a whole is not held up.
If you elect to hand punch the holes allow a lot of extra time and get really sturdy awls for the process. We did that the first two years of our portrait party and it was always a struggle as newbies didn't know how to punch, people got their templates confused,…you get the idea, a lot can go wrong. Most important people wouldn't punch uniformly sized holes and then when they went to sew they couldn't get the multiple thread passes through their holes. That slowed everyone down while we waited for them to enlarge their holes. If you drill the holes and use an appropriately sized drill everyone can sew easily and quickly.
My page, "Portrait Party and Binding Party Information" can be found at this link, or you can look it up in the list of Pages in the left column of this blog. There you'll find links to other instructions for this party, such as a link to the video showing how to fold, collate, punch, and sew the books.