I'll be honest...Giants just cost so much to gain elixir same goes with wall breakers under GiBarch...so Simple barch with wall breakers good too? Pros and Cons to using it opposed to GiBarch?
Im a farming TH8, and I run 75/25% archers to barb split with 2 wall-breakers per barrack. I currently farm in Gold 3, around 1500, and as you can see I have the exact same army as you are suggesting. So obviously, using giants at the number most use, around 8-12 at TH8, is very elixir-heavy with wall-breakers too. With the current elixir drought that is probably not a good idea - however, if you are farming at crystal or high gold, it is more effective at getting to core of bases than WBarch. Wbarch is more for quick, efficient farming without boosts that takes collector raids. In summary: If you can find collector raids efficiently, or there are storages in the outer layer, use WBarch. If there are loads of loot in the core of bases, or you are hitting bases that could normally be barched if not for the fact there are splash and xbows/good point defenses hitting the outside, use giants. Remember, even if you do GiBarch, you don't have to use the Giants every raid - try to use that in your barrack set-up if u do use them.