All data obtained from @SonOfTheBronx on Twitter:
Son Of The Bronx/Programming Insider

May 27th, 2017 (Samurai Jack Marathon)

Time
Show
Ratings
A18-49
11:00am Samurai Jack 1,031,000 606,000
11:30am 939,000 545,000
12:00am 888,000 519,000
12:30am 843,000 495,000
1:00am 786,000 481,000
1:30am 841,000 534,000
2:00am 784,000 468,000
2:30am 704,000 415,000
3:00am 681,000 408,000
3:30am 642,000 355,000


comparison

May 28th, 2016 (Samurai Champloo Marathon)

Time
Show
Ratings
A18-49
11:00am Family Guy 1,605,000 863,464
11:30am Family Guy 1,702,000 926,954
12:00am Samurai Shamploo 1,050,000 587,000
12:30am 840,000 467,000
1:00am 735,000 395,000
1:30am 716,000 365,000
2:00am 654,000 355,000
2:30am 592,000 310,000
3:00am 606,000 324,000

If you want more data, you can check my spreadsheet here. That will have further data including per year difference and A18-49 differences.

Let us know what you think in the comments below about the ratings.