Lilith has an un-submitted 23:38, so I watched it and decided to improve the time by better eco and micro. The farms will expired by the time you finish the level, so no eco tech is needed. Generally you will need to attack directly to the center to open several paths to quickly siege down the rest of the castles. Yellow sometimes will take down 2 castles for you, though not always, so backing up a treb is strongly advised.