Starting from bar 69, 2nd beat (the beginning of the passage in thirds):
53, 42, 31,42
bar 70: 31, 42, 31, 42; 53, 31, 42, 53
bar 71: 53, 42, 31, 53; 53, 42, 31, 42
bar 72: 31, 42, 31, 42; 53, 31, 42, 53
bar 73: 41, 52; then as in bars 70-72
For the sixths:
bar 76: 53, 1, 52, 41; 52, 41, 52, 41
bar 77: 52
Hope that helps.