I understand your need for Cat control, but sometimes you will find RMS's that are very strong due to beamed antennas in your direction.
These RMS's might be way down on your channel list.
The VOACAP propagation prediction program does not take into consideration beamed antennas and station power output.
So, you are back to experimentation at different times of the day to test propagation. The way the oldtimers did it.
This way, you will find your favorite channels, giving your best connection options.
Also, a particular RMS might be scanning a number of frequencies using one radio
Your connect attempt might be on the opposite side of the RMS's frequency rotation.
You might have been able to connect to the RMS, if it was actually listening on that frequency at the time.
By trying a few sequential attempts immediately following each other on the same frequency, you might be getting back into phase again with the RMS.