Can anyone tell me what time the clubs (Adelita's, etc.) open up during the week? I'm coming down on Tuesday morning with a couple of friends and want to know how early we can get some action.

Adelitas opens their door at 10am. I used to wander in about 10:30am, often being the only gringo there and very few chicas. However, chicas start coming in -- as early as 11am there often is a fairly good selection. By 12 noon or 1pm, things start looking really good.

Typically Adelitas is open and ready for you by 8:30....with real talent there by 10am.

You will find bars in TJ that are open something like 20+ hours a day.  (Such as Adelitas.)  However, you won't find much selection during the morning hours.  I enjoy early afternoon to early evening hours, before "bus loads" of mongers arrive.

I believe Adelita's opens up the earliest at 9 am. At that time, you'll probably be able to choose from anywhere from 3-10 girls.

Don't expect much in terms of any girls that are nice looking. Can you say slim pickings?

I did an allnighter and was going to go over the border but figured it would still be too crowded so I walked around the Zone.
So weird not to see anyone around the streets. Mainly delivery trucks and workers walking to their jobs.
There was a few street girls starting around 8 am.

Although technically Adelitas closes, if you are inside when they close their doors at 7am (daily) and can deal with the major clean up and drink something while they are closed, they will let you stay and talk to whateer lady(s) you may still have with you. So long as you are spending money inside, you can stay. otherwise, you have to wait til 10am to be let in.
Besides, the morning girls are not the cream of the crop, so best wait til after1pm for anything you wouldn't mind putting Mr. Happy into.