Okay. Your hands are not small. Perhaps they are a little large. Index finger hanging over the edge of the rubber means not a little hand. It would hang over more if you had really big hands but they are big enough.
If you look at the photo where with the black rubber out where you can see your thumb, if you look at the butt of the handle, and how much of it sticks out below the bottom edge of your hand, you don't need to grab higher up on the blade face. However, if that feels good to you, and you like how your blade plays with the modification you have made, I see nothing wrong with it.
I removed the photos that show how you have modified the blade. But the modification looks okay to me. A few years down the road, the blade could crack at the neck as a result. But, blades break for lots of reasons. So....
BTW: it is your racket. You get to decide which is the FH side and which is the BH side. There is no actual rule on that. It is just personal choice.