I vote for Tues. I was there this Tues and I was pleasantly surprised at the wait times for rides. Our plan was to arrive early but as life would have it we arrived around 10am/10:30am (parks opened at 9am) so I was concerned we wouldn't get RSR FP's. Line to get into M&F parking was long, imo. Parked the car and headed for the trams. Crowded. So to my surprise, as I headed for a RSR fastpass station, we received FP's for 3:35-4:35 return! Soarin was 25 min. RSR was 45 min. Toy Story Mania was 25 min. Our trip was on the leisure side, so we browsed alot, ate alot and still the lines were non existent however the park crowd was dense. We didn't get hardly anything done at DL but Pirates and that was 20-25min. Our main goal was to see the parade/fireworks, rides weren't our priority. When we hoped over to DCA for RSR, the wait time was 80 min. (around 4pm), we waited 20 w/FP!
So if my group trip were designed around hitting the rides, Tues. was very manageable esp. with the heat. Long lines and heat are a bad combo but again we were focused on parade/fireworks/leisurely walking. Parks closed at 10pm and Soarin/River Run/Ariel were all walk on around 9:30pm-closing, not sure about DL side.
Take note: All passes were open.