Armorsmasher: How can Olivia counter tanks best?

With the new update introduced I upgraded the Armorslayer+ I gave ages ago to my Olivia to the Armorsmasher+ (originally to get cheap Dew). Now I actually consider updrading it again after I saw some weird pictures of how Sheena and Nightmare-Jakob (because of 50+ on both defenses) look like now, and I know how weird the BK has always been.

I can't really decide between these three choices:

1. Buff-ignoring-Armorsmasher:
Pro: It's a hard counter to Halloween Henry; it disables Hone Armor so Olivia nearly reliably doubles the BK and avoids damage from that buff. Additionally I love having 40 HP.
Contra: I originally wanted to pierce defenses and defensive Armor Emblems usually word with Ward Armor.

2.Armorsmasher (+Atk):
Pro: More Atk, stacking strongly with the effectiveness; also strong against other units; patches up her worst stat, saving her from Heavy Blade especially if used alongside Delthea. Grants her more reliable KO potential.
Contra: It has the weakest effect of all choices (only +2 Atk) and barely adds to her bulk, which is her most important stat due to being a support unit (although my support units are always strong).

3. Armorsmasher (+Def):
Pro: It adds reliable 4 Def and 5 HP to her natural bulk allowing her to survive much stronger attacks and duels with other Sword-users (most importantly) and probably even some blue units.
Contra: It does not add any damage to her relatively poor Atk stat, which is needed to fight the monsters I want to defeat. Additionally her stat line looks kind of weird then...

A last piece of information here:
My Olivia's curret statline with Armorsmasher+
35 HP
46 Atk
40 Spd
31 Def
30 Res

Can you help me making this decision?