DW and I went last year during this time frame. I would also recommend Monday. We found there was no need to upgrade to FoTL passes. We got there early and were allowed in early. The only thing opened in the park at the time was the Studio Tour. This was probably our longest wait of the day and took us about 30 minutes to get through the line.
After the tour we went down to the lower level and wait times were long. We thought about going back up and buying the FoTL pass. When we went back up, wait times were short up there so we did the top portion. Later in the day, wait times had actually gone down considerably at the lower level. Transformers went from 60-minutes down to 10 minutes.
We're going back again this year, and will probably pick a Monday or possibly Tuesday to go back.