Weapon Equip Order:
Force Weapons & Shinryu Difficulty
Shinryu Difficulty TL;DR
0. Level your strongest characters' Force Enhance Levels
Take turns normally or use a gauge charger (look at the blue bar)
When Gauge is almost full make sure you're setup or setting up AAs, Calls, BT effects
When Gauge is full and buffs/calls/BT effects are in place press the FR skill you'd like to use
During FR phase, fulfill the FR's condition (listed below) as best as possible to get as much damage as possible in the 10T window
You can choose to use Burst Phase during Force Time OR rely on strong off-turn damage (counters/traps) as enemy turns will not lower your Force Time turns but can raise certain FR conditions!
With the addition of FORCE ECHO you can use certain Force Abilities in Force Time (outside of Burst) for big damage, free Force HP DMG Bonus % and 1 free FR turn.
Units at FE30 who use non-attacking skills will boost any gauge by 50% along with any conditions they meet!
Looking for how to budget your enhancement points with the addition of Force Enhance? Check out Enhancement Points!
Rem's Amazing Character list showing FR conditions! (click the image)
A unit with a 0/3 FR equipped and the FR ECHO passive unlocked (top of the infographic - it costs up to 800 enhancement points to unlock it) it can be used during an active Force Time (not in Burst Phase) to unleash it's big attack, extra HP DMG Bonus and maintain FR Time turns.
This Sacrifices holding an Ultima Weapon which may lose out on some Damage and 0/3 FRs only have 1 use. You also don't want this 0/3 FR starting Force Time because it will only be 5 turns and HP Bonus % increases will be half what they would be at 3/3.
FR units without FR Boards can still be incredibly useful especially if their FR has a party aura (HP DMG & Limit are great examples) and good HP DMG Bonus conditions as these units can initiate FR Time and 2 Allies with FR ECHO will have 4 Huge Attacks with all the Echo Benefits
FR ECHO attacks can be used early in the Force Time to setup a big Burst Phase OR they can be used at the end of a Force Time as some deal massive damage thanks to their FR Extensions usually adding more HP attacks or modifying the BRV/HP DMG Limits of the attack. (Just imagine a 6 Warrior Quest with 1 Force Time and 5 FR ECHOs at the end)
It is OKAY if you need more than 1 Force Time for fights. Some fights may even incentivize this with mechanics from revival to HP Gates (preventing HP Lowering until a condition is met). Using a FR ECHO takes up an FR ability use so don't go using them all in one place if you can't kill in 1 FR Time.