Anyone who is looking to get the Rev Ram or Marauder Ram, in my opinion the best time to go for it is at the following time (Sorry I only know GMT and PDT times)
Abassa Server - Port Royal 10pm GMT (6pm PDT)
I know this for a reason as I have luckily got to Wave 79 and picked up the Rev Ram and Marauder Ram at this time, I just happened to go in at wave 3 and was found to be playing along side 2 other players one of them who was getting 100% accuracy 85% of the time.
The Revenant Ram I plundered at wave 58
The Marauder Ram I plundered at waves 78 + 79 (We lost all treasure at Wave 79)
I don't have screenshots of my plundering them, but I have been playing it more often now and Have taken screenshots of my second play so will post them here of my second play Once I have uploaded them to Photobucket
These are my second screenshots of my play unfortunately it's not the Marauder or Rev Ram but gives the idea of when the rams get dropped
Old Cannon Ram - Wave 6
Searing Cannon Ram - Wave 39
Cotton Cannon Ram - Wave 45