If you're only using the Glock for target practice, then the stock sights should suffice. If you're also going to use the Glock for defense, I'd say the XS (big dot) sights b/e of the speed of acquisition. They're not the most "shoot 3 shots in a dime" accurate, but they'll get you on target.
As for ammo- that's personal preference. I practice with the cheapest stuff my range will allow so I can get more rounds down range. I'll also practice a few times with my "Carry" ammo.