The closer to the pistol that the slots are, the tighter it will hug to the body, especially on the grip side. Of course you can take that way too far and make a holster that isnt wearable.
I dont know the rules, if they exist, but I do prefer to leave an ample piece of leather to go behind the belt. If it were me, I would move both of your slots towards the gun. The lead side by not quite a full slot width, and the trailing side by a full width.
Good looking holster BTW.