So I use the Devine Thunder Long Guns on the Bow, Port, Starboard & Stern however you could also replace the Devine Thunders on the Port & Starboard for Heaven's Mandates if you would like a bit more diversity & on the Auxilory I use Heavens Eye Mortar.

For the armor you have a choice, you can go with the Black Prince for added survivability or the Celestial Dance for more status effect dmg.

For the Major Furnature I use Teuiling's Guidence for the additional dmg to weak points with front weapons & since you get 6 gun ports on the Garudas front these are going to be the main weapons you're going to use most of the time.

For the minor furniture's I use
Charge Stores for the increase in the next attacks dmg by 50% after applying storms truck status effect to an enemy as well as the added charge rate increase to stormstruck as well as the additional dmg to electric weapons,
Then we have Copper Fastening Station for increased secondary dmg to electric weapons as well as range increase to electric weapons.
Next I use Amber Station for the increased charge rate & duration of the stormstuck status effect.
High Velocity Kegs for the increased secondary dmg of piercing weapons & maximum range of piercing weapons & since we are using the Devine Thunder Long Guns which are electric & P
piercing weapons it buffs them quite a bit.
For the final piece of furniture I use Kinkel's Laboratory for the Increased Area-of-effect radius of mortar weapons by 5%, the increased armor rating equipped by 5%, & the increased dmg to structures by 5%.