If the E3 has 6 cards, I must correct myself:
6 cards with 2 x BM1680 + 1 FPGA or ASIC each
That´s 12 x BM1680 + 6 x FPGA or ASIC.

Or 18 x BM1680 and one Asic or FPGA for the controlling, if Bitmain connect the BM1680 with each other.

Even Bitmain sell a card with 1 x BM1680 and FPGA since January. They announced a card with 2 x BM1680 and FPGA.