Using a set of triple channel and a set of double channel RAM at the same time

Using a set of triple channel and a set of double channel RAM at the same
time

Scenario:
You have a set of triple channel RAM (3 x 2GB), and a set of dual channel
RAM (2 x 8GB). Both sets are clocked at 1600 MHz, and the motherboard and
processor supports both triple and double channel (i7-950, 3.06 GHz).
The 3x6GB set is already installed. Would it be better to remove the first
set and just have the 2x8GB, or would it be a good idea to keep all the
ram sticks in, and get more RAM (which could be used for RAM disc etc)?
Would installing the sticks in a certain way lose both the double and
triple channel feature?
Without using a RAM disk, the system will in probably never user more than
16 GB of RAM.