The receiver is a Viewsat platinum lite and the lnb is BSC621 C/Ku Standard LNBF - one LNB for both C and KU bands and disecq 2x1 switchThe settings will depend on the equipment.
What are the brands and models of both the C / K band LNBF and switch?
That link tells to use 5150 LO for C-band and 10750 LO for Ku Band.
Here is the manual (PDF) for that LNB. If you are using the onboard switch, it says to use 22 khz OFF for C-band and 22 khz ON for Ku-band.
You could also use a DiSEqC switch with or without the onboard switch.