The start gcode and end gcode in CuraLE when configured for the TAZ Pro should be used in all slicers. You won’t find “better” (or “any”) somewhere else.
The start gcode is fairly well commented and if it was my TAZ Pro, I’d make a copy and print it (on paper). I have extracted the start gcode from CuraLE 3.6.22 and attached it here so I can give some line number references.
TazProStartGcode.gcode (8.4 KB)
In CuraLE, switch from Prepare to Monitor and near the bottom of the window, click the Console button. On the Printer control window, check the Show debug messages box. Now you can enter commands manually and observe the printer’s response.
Using your printed copy of the start gcode, you can enter the commands one at a time (you can skip lines with temperatures) and observe the actions of the printer. Pay particular attention to G28 on line 7, the T0 on line 14, and the T1 on line 19. The G28 should establish where the X, Y, and Z origins (zero) are. The T commands should raise and lower the nozzles.
The G1 command on line 27 should move one of the nozzles over a wiper pad and the G1 command on line 32 should push the nozzle into that wiper pad. The G1 command on line 67 should position the other nozzle over the second wiper pad and the G1 command on line 68 should push the nozzle into that wiper pad.
Finally, the G29 command on line 105 should execute the auto-leveling sequence. Instead of just a G29, use a G29 V4 which will print out the progress. You can click in the Printer control window, type ctrl-A and ctrl-C and then paste the output (with ctrl-V) into an editor to examine it, clean it up, or upload it here. It’s kind of messy with all the temperature reports.
At some point in this process, your printer should do something unexpected. Let us know what you expected (i.e. which command) and what it did.
I did all of the above on my LulzBot TAZ 6 in an attempt to provide decent instructions in this reply. If anything is unclear, feel free to ask.