Help ear training major and minor 7 chords in all inversions

[Pumpthrust]

Been drilling these major 7 and minor 7 chords for awhile using the Tenuto app (mobile version of the musictheory.net trainer).
I do 200 a day in two sets on 100, but each time, I cannot seem to get any higher than 68%. My highest score was 71% a couple weeks ago.
I can't seem to lock my ears on the distinguishing quality of each chord when they're inverted. I can only really hear key centers (in a ii-V-I progression, is this chord a ii or a I?) which may account for my current average score. I also know that some inversions of a maj7 chord may yield a more "minor-like" sound.
I have also tried singing the major or minor 3rd against the chord, but the results aren't consistent.
What are some tips for really getting these chords trained into my ears?

 

[bandcoach]

68% is a bell curve C grade performance which I am not knocking just stating for future reference - it means that you are doing better than guessing

Start with each chord type and only allow two inversions to begin.
20 examples to begin with.

When your identification is above 90% (no more than 2 wrong) then change one out and begin again.

When these are above 90% swap the initial two and begin again.

When these are done
Now use all three.
Examples jump to 30.
Once you get 93% (no more than two wrong), change one out for the remaining inversion.
Repeat substituting each of the three inversions previously used until you get 93% or better on each grouping

Now you do all 4 and increase the examples to 40.
No less than 95% (no more than two wrong) is acceptable now.

example procedure

m7 3rd	m7 2nd	m7 1st	m7	Reps	Accuracy
0	0	1	1	20	18
0	1	0	1	20	18
0	1	1	0	20	18
1	0	0	1	20	18
1	0	1	0	20	18
1	1	0	0	20	18
0	1	1	1	30	28
1	0	1	1	30	28
1	1	0	1	30	28
1	1	1	0	30	28
1	1	1	1	40	38

Repeat for the other chord.

As for distinguishing between them, in all there are 256 possible groupings of these chords and their inversions for testing purposes.
We are really only interested in groupings of 4 or more so all tests that include 4 chords up to 8 chords are needed to develop your skills methodically
- two of these would be eliminated as having already been done (all 4 inversions of each chord as above)
This means that there are 161 different test groupings

I have a spreadsheet with each test grouping if you would like this; pm with a contact point

For each group of chords (4,5,6,7,8) the test examples would be 40, 50, 60, 70, 80 and you are always striving for 90% accuracy in these isolated tests