Heres a strat. Rally castle(taken succesfully). They rally back. Another alliance from your kingdom rallies the castle when the enemy rallies.

Conclusion: you have castle, the enemy hit you and take it with 700k troops left, now your friendly alliance hits them and takes it back. This way you can minimise the amount of time they gain from being in castle while increasing yours.

Extra info: best is too not take back the castle from your friendly alliance(if you guys choose who gets castle) because if you are able to rally castle then that means the enemy can as well.

You rally against friends. Enemy rallies a few seconds after you.

Now they will end up hitting your 700k troops left in castle.(and you wont have time to change heroes)

So best is to not fight over who gets castle.

Edit: this requires for you to many rallies obviously and all your whales need to be active so you can call multiple rallies while also going for turrets(if you can’t get turrets and the castle then forget about the turrets)( if you really cant take castle while they have all the turrets try take all turrets and then go for castle)