I must admit I remain very impressed with Oskar's ingenuity, besides the battery limitations I'm sure his rig lets him explore other ideas such as his quad electric tail rotors. If I were ever crazy enough to undertake a similar venture I would relocate the tail rotors to both sides like elephant ears but on shorter booms. This will then allow both sides to provide anti-torque in the hover and when moving forward one side can be reversed so that both sides can provide a propelling force.
Thanks for the graph Reely340, it really does put batteries in perspective (and also wastage of energy by liquid fuels).