Use whatever is least expensive, it doesn't matter all that much at first as most gun/ammo combinations are much more "accurate" than the shooter. As your skills improve, you will also develop your own preferences in ammo based on what others around you use, what is locally available, and its price among other reasons.
As for sights, the Glock sights were a plain dovetail as I remember and it was no trick swapping out the fixed factory sights for a set of tritiums. I can't think of a reason off hand why it shouldn't be just as easy to swap in a set of adjustable sights but I do believe these latter are rather pricey. Myself, I would probably just shoot what is currently on the gun until I decided my abilities were such that the sights are holding me back. Like many, you may find no need to change or that a simple change of inexpensive front post or rear sight is all that is wanted.
As for sights, the Glock sights were a plain dovetail as I remember and it was no trick swapping out the fixed factory sights for a set of tritiums. I can't think of a reason off hand why it shouldn't be just as easy to swap in a set of adjustable sights but I do believe these latter are rather pricey. Myself, I would probably just shoot what is currently on the gun until I decided my abilities were such that the sights are holding me back. Like many, you may find no need to change or that a simple change of inexpensive front post or rear sight is all that is wanted.
