It depends on what is most important to you.
If making sure that you have the least amount of couch-lock effect is most important then harvesting now would not be a bad decision. If you are willing to risk slightly more couch-lock to get a couple more grams then wait. It is not like you will get an extra ounce waiting.
If you wait look at the trichomes every day and at the very first sight of the slightest bit of amber harvest.