Barching in Gold should always be an option. I boost twice per day when DE farming and saved enough for the lvl 22 AQ in 2 days. You just have to be efficient and Barch due to the build speed. Get in, loot, get out... rinse, repeat. It builds up fast. Just pick bases where you only have to go through 1 or 2 wall layers to get the archers within reach of the DE. Dump the gold & elixir you get into walls if all other items are upgraded already.
Let me know if you have more specific questions. I only use Barch and my AQ for DE farming and typically stay in Gold II(ish).



