John:
I'm sure you already know this, but being a rifle shooter your whole life let me remind you that there are three crucial things you need to concentrate on to shoot a target handgun well:

1. Front Sight
2. Front Sight
3. Front Sight!

The rear sight is only there to give you a light-gap either side of the front sight.

If you are fitting optics or holographic sights just ignore the above!

I well remember not being able to hit sh!t with the first handgun I was required to use a lifetime ago, a Ruger .357 Security Six, until someone explained the sighting difference to me. I was trying to sight it like a rifle: hopeless! No longer remember who gave me that sage advice, but I am forever grateful.

French connection? None. Thread well-and-truly hijacked now!