YVW... the three of us who responded have been using Lacerte for eons. We've learned, the hard way, that the 'hurry up & wait' approach is the best one.
It is especially important for the proforma process as issues with that can impact the actually preparation (and accuracy) of the 2020 return.
I will transfer a few to play with, or to use for year-end planning. I then transfer those again when I think the program is 'ready for prime time' - be sure to renumber the planning one so it doesn't get overwritten.
IF there are major issues with the program (stick around here, and you'll hear about them..) I will wait & proforma the clients one by one as needed. It's not my preferred method, as I use the 'status' function to track work flow.