Playing the Light & Darkness stuff in a scenario like this, is very good! You can start your turn by going into Sheou directly! But if they Imperm/Veiler the fusion attempt, we'd have to get Changeover with Chamber, losing access to adding Tidying, to make sure we'll have Sheou + LaDD.

Even tho it's good to play the LaDDs, in the main deck I'd suggest only 2 Dark End Evap and 1 Light End Subli, more than that will be too bricky. There's also the possibility of going into Light & Darkness Dragonlord without them, but it's kinda tough, needing many DARK Dragons in hand.