With the same amount of Quantum or Amethyst Towers the Shield can even absorb 2 damage more, because the mark is worth 3 damage (only 1 with the Field). Just 2 damage, but the could save you
. However each used quanta for other cards will reduce your max possible damage absorb by 3 and not only by 1 like with the Field.
And I dont know how it really works unupped. Does it round for each Monster or in total?
For example you have 2 monster(10 and 4 damage).
Is it:
10/3 = 3,333 --> 3 quanta +
4/3 = 1,333 --> 1 quanta
= 4 quanta
Or:
(10+4)/3 = 4,666 --> 5 quanta
I dont know, whether it keeps the position after decimal point for each monster in mind(1,333 + 3,333=4,666) and rounds after or not.
The difference is at most just 1 with 2 monsters, but 1 unequal 0 and with further monsters the difference could increase.
20 monster with 4 damage
4/3 = 1,333 --> 1 quanta * 20 = 20 quanta
or
(4 * 20)/3 = 26,66 --> 27 quanta