Don't copy paste your details.
I disagree. Knowing when to copy your stuff and make it look like it wasn't copied is a very key part of optimising your mapping. You will be a lot faster if you can do it right. No point in rebuilding that group of barrels when you can just copy a previous group and move some, change their skins a little. No one will ever notice and you save a tonne of time.
I've always favored the approach of making a fully detailed version of your first alpha, to use as a sort of 3D flyaround-able concept art. That way, you know what you're aiming for before you ever start testing, and have a good idea of how far you can stretch the layout once changes become necessary.
Sorry for de bump, but I feel like I have to ask: Why did Ravage edit-remove these posts? It's not the only place he did that. Is it something that's no longer relevant? Is it something else?
There needs to be some sort of edit/removal protection on this forum to stop people from spite-erasing their posts. If not by locking down posts that are a certain age, then by auto-detecting repeated attempts to edit different posts and locking down the account until an admin can resolve the issue.