I think the first step is to figure out why the ones you have are not overlapping. This sounds more like a hardware problem than a drapery problem, unless your drape are not wide enough to meet. Could you take a photo of the current drapes at the top where they are not coming together?

I don't have any drapes yet -- I'm looking to buy some. The ready made ones I'm seeing in stores, like the back tab, the rod pocket, and the grommet, don't overlap.

JC Penney used to be the place to go for these. Unfortunately pinch pleated drapes have all but disappeared from the market place. You could check their web site to see if they are still selling them.

I checked Penney's, but their pinch pleat drapes have the back tabs which meet, but don't overlap, in the middle.
I'm pretty open to other kinds of drapes, just want them to perform properly.

Country curtains has a limited selection of pinch pleated draperies and sheers.

The Shade Store fabricates draperies that are what I would call semi custom. Limited selections in customized lengths, with different top details available. They are relatively expensive but not as expensive as custom. (Probably more expensive than some seamstress-made simple panels)

The hardware will determine whether the drapes are going to overlap. A standard traverse rod, which is typically used with pinch-pleated drapes, has a master carrier at the leading edge. It extends the end of the fabric out and allows it to cross over the master carrier of the opposing panel, thus providing the overlap that you want.

Go to the link below and look midway down the page at the drawing titled: How a Decorative Traverse Curtain Rod Works. The drawing shows how the two master carriers come together and overlap.

Traverse rods are not seen as much these days because many people are using stationary panels. You are correct, the back tab, the rod pocket, and the grommet types of drapes don't usually overlap, and in fact, many times don't move at all.

Here is a link that might be useful: Traverse Rod

I was recently in Penney's looking for drapes w/o those d*** grommets, and saw the pinch pleat 'Royal Velvet' line on display, since it was the fabric I was wanting. They were on a traverse rod, which you need for overlapping, and from where I was standing, looked to overlap about 4". I did end up finding them in a rod pocket/ tab top, and although I would prefer an overlap, it's myself who has to install the rod!

In re-painting a living room in my second house, I told the painter to take down the old traverse rods and "throw them out!" He put them in the garage temporarily. Fast forward to decisions about curtains. I started pricing out curtain rods and, traverse rods are in the thousands! "Yikes!, said I! Run to the garage and re-install the old ones!" They work, even after 60 years, and they look fine.