tinitus said:When you have 3 coils, you use a combination of fig 5 and 7
Personally, I would shoot for using 6 combined with 6. Place another coil on the top left above the two shown in 6 with its axis 90º to the right coil. Darren Kuzma, formerly of PE, once told me you never want to be able to look through the hole of one inductor and see another one, unless they very far apart.