Defense strategy - How to Defend your castle Good Game Empire
To consider whether 100-0-0 or 50-0-50 is better (98-1-1 and 49-1-50 should only be used with defending RVs due to a glitch that means you can't have any 0s on any flank or risk losing the RV whatever happens) it is important to consider how many troops you are likely to have defending it and lose on each flank. The idea behind 50-0-50 is that IF both flanks are defended than you will get a +30% bonus in the keep.
This has caused a lot of debate since when you are offline you cannot necessarily assume the type of attack that will hit.
It also depends on whether your castles/OPs are fully built in terms of towers.
In general I would recommend 50-0-50 for any castles which are fully built (with 260 men on the walls, since 130 men on each flank should be able to destroy the enemy attackers who will be attacking in groups of roughly 50).
A level 3 towered castle will only have 200 men so I'd recommend going all 200 on one flank-you will take very few losses on the flank but if you were to have 100 men on the flank you risk losing that flank and going -30% in the keep which can be devastating.
In short the level 4 towers are critical to a 50-0-50 defense.
As to armourer tools being left in when offline this can be an issue due to ''tool-cleaners'' but there is not a lot that can be done about it. I am not aware of your circumstances, ie if you get a lot of pile-up attacks but in general I'd leave at least 12 of your best tools and DEFINITELY fire moats in each slot possible. Fire moats in particular mean that attackers on the flank will not be able to use either a) ranged bonus tools b) moat tools or c)wall tools.
As a side point I'd recommend skewering your defensive mix more towards melee ie leaving your flanks at 60% melee, 40% ranged (if you have no ranged def bonus defensive tools), since if they then attempt to really destroy your ranged defenders with mantlets, your melee troops will receive a bonus and in fact melee troops have an effective defense stat against ranged attackers, especially with a significant bonus. On the other hand ranged defenders cannot do anything if their effect has been cancelled out with shield walls etc.
I hope this helps!
As to when to use tools though that is basically your choice but I would say it is best to leave a few armourer tools in offline. (If you're short on tools in general you can always stick in basic ruby tools and go 100-0-0 but this is a defense that will be hurt bad by an armourer tooled up attack!).