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Darl, you may have found the answer, but I didn't see any response to your message. You are correct about the alternate F1 - F6 functions not being explained in the User Guide. In the WSJT-X main window, however, if you select the Help - Keyboard Shortcuts, you will find it in the parenthesis for F1 to F6.
F1 = transmit Tx6 (CQ)
F2 = transmit Tx2
F3 = transmit Tx3
F4 = transmit Tx4
F5 = transmit Tx5
F6 = toggle "Call 1st)
As you already know, they are activated in the Settings - General, check "Alternate F1-F6 bindings".
There is no F key for Tx1, as the software intentionally requires you to actively make the selection of which station to call, if you are not the CQ-ing station.
73 Frode LA6VQ