well.. I've been reading - reading.. the strategy. it's written.. but the topic doesn't have 6-7 pages. just questions and bashing Castle. :).
it all depends on the map.
for example, when playing by chaos rules. on the 12XM6 template (I don't remember exactly, the start is definitely on 12) Castle is just deadly.
overall, the strategy for playing Inferno boils down to the following:
1. start with Pyre with the machine gun
2. find a fast stack. and use the machine gun to clear the respawn. usually this stack consists of Efreeti, which are quick to get into action.
3. the main goal and strength of Inferno is to accumulate a strong strike stack of Demons. any unnecessary low-level monsters go into that.. yes, it requires a bit of hassle and skill ;).. but there are experts who have 300-400 Demons by week 3. with such a stack, Dragon Utopias are easily broken :) besides, Pits can be used as makeshift Archdevils for resurrecting the army in conservatories, which is a strong asset.
but I don't like playing this town :)... due to its peculiarity.
300-400 Demons by the third? Well, it seems to me that's impossible, unless with Diplomacy. And you don't even need that many; 60-80 Demons are quite enough to deal with any conservatory and Dragon Utopia.