hi @growlingflea ,
Check out this thread:
Upgrading from v4.2.2 to v6.0.0 10% per hours
Ensure that you update your 6.0.0 package with patch 1 before you run the upgrade, which should markedly increase the speed (it places indexes on the uuid columns before adding them).
Should be ok to go straight from 501 to 600
Do not need to add uuid’s to custom tables.