Put the Misplaced Promissory Note's effect the defensive armor sets/trinkets

With the introduction of the Misplaced Promissory Note trinket the ability to tank may be around the corner.
My suggestion is to add this effect to the following lines for the(damage type it effects): plate(normal), jelly(piercing), skelly(shadow), magic(elemental)
I also advise making the damage resist trinkets have this effect(jelly,skelly,crystal)
Also maybe make the Misplaced Promissory Note available for about 30-40 jelly gems
My 2 concerns are:
1.the lack of a ability icon makes me fear its a flat effect, does anybody know if the effect is doubled if you two Misplaced Promissory Notes?
2. the plate armor may still be under powered
Thank you for giving your time to read this :}

The current note gets nullified to a certain extent by sonic mode. Who cares if your defense is higher when you're guaranteed to live from the attack.
Having higher defense the more health you have could be a really interesting mechanic.
Maybe going into negative defense if your health is on the low side.
I think the promissory note should be reversed in its effect. Yes, it's more exciting when the player is at low health but trying to stay at high health would be more.. functional. I.E. The higher the player's health the more defense it would add.