You could use either a DiSEqC or a 22khz switch.
I'm going to set my QPH Invacom up using a 4 x 4 multiswitch, which incorporates a 22khz tone switch to select between the two sides of the LNBF.
The two circular outputs from the LNBF go into one set of inputs on the 4 x 4 (either sat A or sat B) and the two linear outputs go into the other. One will be selected with 22khz on, the other with it off. The 4 x 4 will allow up to 4 receivers to see either the linear or circular side of the LNBF at any polarity.
Since the linear side of the QPH is standard (L.O. 10750), the 22khz will work fine. You could also use a DiSEqC switch, but this solution seems more efficient to me. Of course, if you're adding a third LNBF into the mix, you would have to use a DiSEqC switch because 22khz only switches between 2 LNBFs (or, in this case, the two sides, circular and linear, of the QPH).
It is best to install any switch between the LNBF and the motor to avoid damage to the switch from motor current. So the connection order would be RECEIVER > MOTOR > SWITCH (22khz or DiSEqC) > LNBF