Everyone seems to have different idea as to the proper mixture of ALC and drive power when using the IC-7300.  The attached document is from Icom and describes the correct setup for the IC-7300 and other Icom radios.  The key takeaways are:

1. No ALC
2. Power on the radio at 100%
3. Adjust output power with the power slider on the right in WSJT-X

As I think this through, using this method will require some care when switching from a digital mode to SSB/CW if a amplifier is being used.  When in a digital mode the drive to the amplifier is set using the using the power slider on WSJT-X.  No problem.  But if I now switch to SSB the PA will see the full 100 watts of drive. Probably not a good thing!  So the process to switch from digital to SSB now becomes;

1. Cut the drive power back to a safe level (20-30 watts with the Beko for example)
2. Switch to SSB on the 7300
3. Check PA power out and adjust if needed
4. Have a nice day 

Note in their discussion the relationship between ALC and power out of the radio.  

Johnny K4SQC