it's a common knowledge that:I wish someone might have mentioned that Plus LNB's were not going to work but what's done is done.
1) any DPP device has internal committed diseqc switch.
2) you can not cascade committed switches.
I wish you read more before ordering anything.
22kHz switch (tone-switch) instead of diseqc switch may work for you.
But you need the one which passes tone signal to both inputs (Chieta switches would work).
Also, DPP Twins need more current then average LNBs. And if you feed all this current (for both DPP Twins) via tone-switch, you will most probably fry your switch.
You may need to put power inserters (between tone switch and each DPP LNB).