[Elecraft] K3 KRX3 - BNC or KAT3?

[N2TK]

I think this was addressed before with not having the KAT3. I do have the
KAT3. Is it recommended to hook up the  BNC connector on the back to the
KRX3 or to use the second SO-239 on the K3 or does it make any difference? 

Most of the time I will be using the same antenna for both receivers. When
the K3 has the capability of having the two receivers on two different bands
I would like to monitor another band with a second antenna. An example would
be to monitor 6M. Figured I could use the second SO-239 for this.

I assume that when I am listening to both receivers on the same band that if
I am using the receive antenna input the receive antenna will go to both
receivers. Is this correct? 

Tnx
N2TK, Tony
K3 #311
K3 #1435