I've gone with just barch. Revenge zapped TH9's and 10's that wrecked me. If you do choose to zap, I'd only do it sparingly. Much better to zap a mortar out and go for the storage. Obviously with barch I only targeted poorly protected storages and filled drills.
I never pulled in a lot per day. I only had a few things I wanted to do with DE at 8. Got my BK to level 10, maxed my minions and got my golem to level 2. Haven't touched my hogs or valks yet. I wanted the golem done since I plan on focusing on the AQ until she's at level 10, with some BK levels mixed in there.
I don't think it's really necessary to get too worked up over DE at 8. Decide what you want before moving to 9 and just go for that. There will be plenty of time to catch up on dark troops when DE is far easier to acquire.
personally ive been grinding about 8-9k de at ease. im 2 months into a TH8 and have near max defenses, just some bombs left. Hogs are already underway to lvl 4. BK is at 7 , going to 8 tomorrow
Ive found 1350-1500 a decent range to get it from the storages .
troop composition -
8 giants, 5-7 wiz, 4-6 WB, rest barch and about 10-15 gobs for emergency. ohh and all lvl5 wiz in cc for extreme emergency situations only.
if its buried too far deep and the defenses n walls r tough i wont bother, but if doable which is most of the time , i will get it, i may use a heal or 2 i also carry a rage , i try and avoid all spells unless needed.
Also if its a Th10 i attack blindly cause of the loot penalty, th9 maxed i would think twice unless he has 2k de then i will go for it anyways. People do revenge and you gotta take that into account
I rarely get any loaded collectors and that isnt an issue. i also make sure i have at least 1.5 - 2mil elx cause u ccan burn thru it if u dont get any , i usual do get 100k odd every other attack so hasnt been an issue. Hope this helps