Just recently installed a BLTouch v3.1, and flashed ADVi3++ v 4.0.6. Love it ! Just installed the Octoprint Plugin for Bed visualiser. Will this starting G-code work :
M155 S30 ; set temperature reporting delay, use a value longer than the time it takes for your leveling command to complete. @BEDLEVELVISUALIZER ; instruct plugin to start recording responses from printer. G29 T ; report the bed leveling mesh points. M155 S3 ; set the temperature reporting delay back to a shorter time span.