While the 200 boost is a massive effectiveness jump over the 125 boost and
Crisp Blue Tunic is nearly a must have for 2p battling from about 180-300 HP;
Tabard + Gshield is predictable and easy to beat.
Combined they offer the following defenses :
Icons (Defended at 200 Def, Defended at 250 Def)
3 Light (13.5, 16.5)
5 Fire (22.5, 27.5)
6 Air (27, 33)
8 Earth (36, 44)
10 Physical (45, 55)
All Dark
All Water
As you can see, Light is the best option against the combo, with Fire and Air not far behind. So you'll want weapons or weapon combos that deal large amounts of light, air and/or fire.
I'm going to assume that you are only 125 Str boost for all of these:
Portable Kiln does 33 fire damage all by itself, more with stance multipliers. That will get damage through, and if you have a second fire weapon or species attack that adds fire or if you use an offensive stance, you can get more through.
However, that is somewhat vulnerable to reflection, so let's look at some other options:
If they are using both at the same time, they are only able to harm you with species abilities, so packing a full blocker/reflector combo against their species abilities can get render you immune to their attack while dealing a small amount of reflected damage back at them. Be warned that using such tactics may force them to go on the offense, so be prepares for them to switch things up after a round or two.
While a bit iffy on any given round,
Glittery Faerie Dust deals 45 damage of a single icon type. That's an average of 11.57 damage against a 200 defense boost and 8.43 against a 250 defense boost. If you can combine with another weapon that either blocks their species attack and/or helps to overload one of the weaker defenses, this can easily work out to an average win in damage per round. Dual GFD is strong, but the math on all 49 combinations is more work than I have time for right now.
Dual
Wand of Reality gets you 10 icons of light and air (30 damage each) which can stack with many species abilities. Upgrading one or both to
Pirate Captains Cutlass adds more air and physical.
Ring of the Lost has 5 fire icons and 4.5 light. Add another fire weapon such as
Garoo Elite Blaster to get to 30 fire damage, or a heavy light weapon such as
Staff of Righteous Fury to get to 34.5 light Or double up on both with RotL +
Skeltal Fire Gun (33 fire, 22.5 light) or
Amulet of Thilg (24 fire, 37.5 light)
And of course, against low-offense, high defense pets late freezing should be a consideration. If you can survive them dealing 100+ icons to you, they are only likely to win on a first round freeze if you open offensively or if they have weapons better than those currently in the hidden tower.
In that vein, multifreezers should be a consideration. If you play defensively, shutting down half of their species attack and using a defensive stance the match might get slow enough for you to wait for
Slumberberry Potion,
Pearly Koi Bubble Net or
Meerca Mesh Net to give you multiple freezes to go all out against them without their defenses.