The SIL and MS series are in-line single reed relays shown here, the top image, the distance within the SIL relay from A to B is approximately 0.70 inches which is a little shorted than the LP relay. So it should so have better RF characteristics because of the shorter signal path. The MS relay is even better and is only 0.50 inches inside the relay from point A to B, so the RF characteristics will be better still. Note however, the reed relays still have the inputs and outputs going through the PCB on both sides of the relay.