The level 6 balloons can be get by request for clan castle troops, so the 220 spaces are army camps + clan castle spaces. This works well against town hall 8 bases with air defenses behind one wall.
Army Composition:
(No army intro)
Minimum Troop Housing Space Required: 200 Minimum Spell Housing Space Required: (not specified)
use clan castle balloons to destroy the first air defense
drop 2 dragons to clear the path to the last air defense
once the path is cleared, drop the rest of your dragons and eliminate the last air defense
enjoy the 3 stars
(No execution notes)
Conclusion:
if you are waiting too long for the witch and valkyrie in your clan castle in order to complete the Dragon/Wizard strategy that i posted yesterday, you can try this one. Barbarian king is not neccessary recommanded here. If your opponent has a cornered building, trade one dragon for 20 archers. If you are in a lvl5 clan then you can always expected to get lvl6 balloons more quickly due to clan perks and most of your th8 players have lvl5 balloons. Not necessary to be lvl6 balloons in the clan castle, lvl5 balloons works as effectively as well. You can trade one dragon for 4 of your balloons too, to ensure destroying the air defense that behind one wall