Ok.... using the same testing method as Iresire used from
Blue Gartr here are the numbers I got:
Test #1
Confirmation
Before I did anything I wanted to confirm the base knowledge of Mana Wall: The 2hp = 1mp convertion.
To do this I did not use the Terra's staff nor the goetia's sabots +1 for this test.
Mp before 1000 Needles: 699
Mp After 1000 Needles: 199
Total Mp Lost: 500
As you can clearly see the 2hp = 1mp convertion is true
Test #2
The Goetia's sabots
Same as Test number 1 only differnce is that I have the feet in question equiped now:
Mp before 1000 Needles: 891
Mp after 1000 Needles: 459
Total Mp lost: 432
As you can see under the sabots I took 68 less damage (Mp) from the attack.
Test #2 was done in an error had pdt 4% on at the time of the test.
Here are the numbers done without pdt:
Mp before 1000 Needles: 917
Mp after 1000 Needles: 467
Total Mp lost: 450
Test #3
Goetia + Terra = ?
Now lets see what happens when -20% Damage reduction is added:
Mp before 1000 Needles: 869
Mp after 1000 Needles: 509
Total Mp lost: 360
So with the sabots and the Terra staff I took 140 less mp loss then I would have without them.
Keep in mind so far I've only done test numbers 2 and 3 once. Im gonna do test number 2 a few more times to see weather or not the mp loss will change.