McGuyver -
The blind scan only scans the current satellite. I too had thought maybe it swept the clarke belt before I got into this hobby further. However, the blind scan simply scans the biggest possible array of frequencies (not just the standard/set ones) available for your lnbf and identifies all channels that it finds. (maybe someone will pipe in with a more technical explaination, but that's the basic)
You've answered quite well, this means that it will find TP's that aren't already programmed in the receiver. thanks!
As for SatMex5 being weak, you may want to pick another sat close to your true south. Then use ULAS positioning in your satellite options to move your motor to that position. Then you know that your motor is positioned at where that satellite "should" be given your long/lat location (as long as you've set your elevation correctly). Go to your dish and gently/slowly pan the whole setup (motor and dish) left and right a degree or so at a time in attempt to catch the signal from that satellite. If you find nothing, the adjust your elevation on your dish (no the motor) and try again.
Then providing my elevation is set correctly, USALS will pan the belt and seek whatever it can? Am I close?
That can be a slow and frustrating process depending on how far off you are on dish elevation and such, but it will work as long as you have your motor elevation right, your dish mounted on the motor's post correctly, and your pole exactly plumb.