How it all got started
Thanks for asking our opinions and welcome to the forum.
The empty chamber thing got started when people realized that if you carry a gun around all day with a percussion cap under a hammer, anything falling on that hammer (or the gun falling and landing on the hammer) has a good chance of setting it off. So, unless preparing for an imminent firefight, it was normal to leave the hammer down on an empty chamber.
Not necessary with any revolver of modern design. Transfer bars, hammer blocks and such design features prevent that sort of accidental discharge. Revolvers not using those design features do not have that organic safety. Good replicas of older guns and cheap (in the pejorative sense of the word) new guns are not that safe.
For the GP, all chambers loaded is as close to perfectly safe as you can get.
Semi-autos have a slightly different history.
1) If you drop a 1911 style gun on its muzzle, the inertial firing pin has a possibility of hitting the primer. Colt and some other manufacturers have updated the 1911 design to include a firing pin block that prevents that. But many other makers do not have it. Some people carry with an empty chamber to prevent that possibility with 100% surety.
I do not remember if Glock has a firing pin block. But I suspect Gaston would have used it or a similar technology in his drive for safety.
2) Some people are just nervous with a cocked hammer behind a loaded chamber. Manual safety or not. While Glock does not have a manually operated safety, it does have a longish trigger pull, as the action starts with the hammer/striker only semi-cocked and the trigger has to move deliberately over a finite distance in order to fire the gun. Again, this gun is as nearly as safe with one in the chamber as it is empty.
The condition of a gun with empty chamber is often called the "Israeli Carry". Google it. Supposedly, the Israeli Army required its troops to carry in that condition except when actually preparing for an imminent fight. Also Google "Condition One", "Condition Zero", "Condition Two" and "Condition Three" for more history on whether to keep one in the chamber or not.
I would only recommend a chamber-empty condition for a home defense gun if your early warning system gives you PLENTY of warning time and is 100% effective and reliable. Otherwise, the half-second extra time to rack the slide could cost you. And the extra second and a half doubt asking yourself "Is there one in the chamber or not?" could cost you your life.
There is no sound so load as that of hearing "Bang" when you expected a click, or hearing a "Click" when you expected a bang.
Whatever you do, practice with it and do not vary.
My home defense gun has one in the chamber under the hammer and I recommend that for both your Glock and your GP.
I also recommend keeping the GP, as the other shooter in the house finds it more comfortable. Confidence in home defense is important. She is confident in her skills with the GP. Decision is made until she practices enough with the Glock to have greater confidence in it.
Lost Sheep
P.S. We have not addressed what ammunition choices you have made, nor the other features of your overall home defense plan. But you did not ask about those.