I usually do #1 but not for DE since I never really get to it with just barch, but with #2 and #3, whenever I see no loot in the collectors, I just try to find an easy path that leads straight to any storage has more of the loot, if you understand what I'm trying to say.
I usually try to find bases that have a majority of the loot in the collectors, which usually it helps me quite a bit looking for bases like that. But when I find a base with a ton of loot in the storages, the base is usually a maxed townhall 9 or mid maxed townhall 10, which most of the time is disappointing because I don't have Balloonion or GoWiPe ready for taking on said bases, but oh well.
For what it's worth, I'm finding Crystal II a bit of a waste land when it comes to loot. I highly recommend sniping your way through this league if you've got the time and decide to head to Masters.
Unfortunately I don't have the time to sit and next through snipes - which are not all that plentiful. It's build army, raid go off line, get sniped, build another army.
As a side note, my L6 Barbs finished last night. I had put off doing them for other stuff but I will say they are a very nice addition to Barch and GiBarch for farming. Makes getting 50% a lot easier.
L6 wiz are kind of nice but they aren't THAT much better than L5s only a few more HP and 10 DPs. Yes that can help in war but L5s are pretty good.
Barbs get small boost individually but remember you often bring 80 - 120 of them in a farming raid which adds a lot.
And remember the Iron Fist summons barbs the same level you have so upgrading Barbs actually makes your king stronger too.
I guess that's a long winded way of saying I'd do Barbs ahead of Wizards.