One-click logging from WSJT-X can be done into any of the 3 major loggers using JT-Bridge available from http://jt-bridge.eller.nu/. One-click (or "no-click") logging from Fldigi to MLDX can be setup using either a macro AppleScript, or through the AutoLog script (with full setup instructions) included in the MacLoggerDX Extras folder. The applescript macro is perhaps the easiest way to go, but the AutoLog is the most painless once it is setup. The UDP feed has NOTHING to do with logging from Fldigi or WSJT-X to MLDX. It only pushes data out from MLDX.