When (if ever) should I separate them?

I'm a newbie with 23 chickens, now 8 weeks old. Six of them are dark Cornish, which we will send to the freezer in the fall (when they are about 22 weeks old).

Right now, there are 4 roosters (3 dark Cornish and an EE). I read in one of my chicken books, that with "heritage birds" (which I believe dark Cornish would qualify) you should separate out the roosters at 10 1/2 weeks. At 8 weeks, the EE rooster is attempting mating, the dark Cornish are crowing but not trying to mate yet. We don't think we want to keep a rooster, so the EE will likely go in the fall also.

This is my current plan: Hang a tarp down the middle of the coop and run, tying the top to the ceiling and weighting the bottom with bricks. We have 2 pop doors and plenty of roost space. I'll put all the bachelors in the smaller half. I have not done this yet, partly because it will be a real pain setting it up and slipping through a tarp to feed and water, and plus, there has been no fighting or major harassment of the hens so far.

My questions:
1. Should I separate the roosters from the hens now, before they start mating with the flock? I read on here that removing a rooster from his flock may make him get depressed and stop eating.

2. Will a tarp be enough separation? They won't be able to see the hens, but they will definitely hear them. I really don't know where else I could keep them. We have a simple chicken tractor, but it only has chicken wire and no shelter (definitely not predator-proof).

3. It will be necessary to separate them eventually (before 22 weeks), right? I am assuming they will fight each other and harass the hens.

I appreciate any advice, if someone has experience with this type of situation.
Thanks!
Robin