Hope you have seen these:
We now proceed to the third innings:

The cutoff here is 50.00
The first surprise here is that Bradman does not appear. Perhaps he did not bat enough in the third innings.
The leading batsman PBH May is a bit of a surprise. He is followed by JH Kallis and DCS Compton.
No current player appears in the top 10. The only players from recent times are K Sangakkara who retired in 2015 and HM Amla (2017). Batting in the third innings must have become more difficult in recent times.
From India there are M Amarnath and VVS Laxman.
Now for the fourth innings:

The cutoff here is 40.00.
Headed by Boycott, Gavaskar and Hobbs.
Current players here are KS Williamson (at 7), Kohli (at 8) besides recent player Younis Khan (at 9).
Other current players include AD Mathews (has he retired from Tests?), DA Warner, DM Bravo, Shakib Al Hasan, Asad Shafiq and R Taylor.
From India there are Gavaskar and Kohli in the top 10, followed by Dravid and Laxman.
It would seem that recent players have coped better with the fourth innings than with the third innings.
Another interesting topic to study would be the batters and bowlers who have done best in the fourth innings.