OK, well first things first, I've gone past Fatum's streak of 251 in the battle castle. I didn't save the 252nd battle since I had a saved battle I didnt want to wipe, but I recorded battles 246-252 and have uploaded them to youtube -
check it out 
Here is where I am up to now:
It is also where I will be staying for the time being. It's unbeaten, but I don't see myself extending it for a while. I think I might give the battle tower a go since I want to try out a Soul Silver suicune I got in a trade.
Anyway, my team is almost identical to the one I posted earlier, apart from rebreeding my old salamence and blissey to get shiny ones. I also moved the spare 6 EVs from HP to Sp Def on salamence because, with equal defenses, download pory got sp atk boosts when it switched in to salamence, which was annoying - now it gets useless atk boosts no matter who it switches in to. So, here they are:
Salamence - AXL (shiny)
Jolly - Intimidate - Male
IVs: 31 / 31 / 31 / 24 / 31 / 31
EVs: 252 Attack / 252 Speed / 6 Sp Def
Item: Choice Band
Moves: Outrage, Earthquake, Aerial Ace, Rock Slide
Milotic - AL (dive ball)
Bold - Marvel Scale - Male
IVs: 31 / 14 / 30 / 30 / 30 / 31
EVs: 252 HP / 252 Defence / 6 Speed
Item: Leftovers
Moves: Surf, Ice Beam, Toxic, Recover
Blissey - ANGEL (shiny)
Bold - Natural Cure - Female
IVs: 31 / 4 / 31 / 31 / 31 / 31
EVs: 252 HP / 252 Defence / 6 Speed
Item: Leftovers
Moves: Seismic Toss, Flamethrower, Softboiled, Aromatherapy
I didn't breed a shiny milotic, because Al is already such a beast. It has 56 ribbons, and was caught in my original Emerald game, so there's no way I'm going to swap him out.
Anyway, I've mentioned the strategy before, and it can be pretty much deduced by watching the video. But a few basic things:
1. Before EVERY battle I identify every one of the opponent's pokemon, and generally check their summary. Then I compare it to the moveset list - only in very rare occasions will I need to pay to check the moves as well, if there is more than one of a certain pokemon with the same stats and item, which poses different kinds of threats to my team. For example, jolly focus sash houndoom - one has counter (I use milotic to deal with it), the other has reversal (salamence takes care of this one, although it nearly screwed me over big time in the youtube video because of paralysis on thunder fang).
2. OHKO users are promptly sent down to level 45 so they don't pose a threat. These guys are the primary source of problems to teams like this in the battle tower.
3. Anything I know for certain can be handled at level 55 is leveled up to get me more castle points. Probably not much point detailing how I decide this. Hmmm I wonder if blissey can handle that modest bastiodon, or if salamence can OHKO that sash'less lead heracross.......
4. Toxic on milotic is very useful for killing bulky pokes (milotic and blissey can stall/switch/whatever while the foe slowly dies). It is also crucial for dealing with some salac/reversal pokes - hit it with toxic, and then KO with salamence without fear - even though salamence resists reversal, it is not worth risking a possible crit, and then seeing the rest of my team destroyed. Even activating guts on heracross is usually worth it (sacrificing milotic or blissey to get salamence in safely). Also deals with focus sash/band to an extent as well. It has to be said that occasionally getting poison synchronized from an umbreon has helped milotic later when facing a powerful sweeper.
5. Blissey and milotic try and heal themselves towards the end of the battle so there is minimal cost in healing my teams between battles. Toxic really helps with this, as they are often slower, and can recover/softboil after taking the last hit, just before the opponent finally succumbs to the poison. Roost would be an interesting option on salamence for this reason, although it obviously doesn't go well with choice band (lol), and I don't want to lose the power by switching to leftovers.
6. In most battles, salamence is just there for intimidate (I've never once had to restore his PP), but he occasionally does get to rip through a team just using outrage.
7. Finally, possibly the most important thing. NEVER be a scrouge with castle points. Lower the opponent's level if you feel you must. In extreme situations I even passed a few battles (probably about 3-4 in my streak so far). It sucks, and you lose LOTS of points (50 plus the points you don't get for winning the battle), but it's better than losing and dreaming of all the points you saved. The last one I remember passing had I think that focus sash exploding electrode, another bulky exploder with a quick claw (golem or claydol?) and some kind of bulky normal sweeper. It's just not worth risking it.
I also uploaded
another battle to youtube this morning. Apart from being the 300th in my streak, it also featured the first shiny pokemon I've ever seen in an opponent's team in a 4th gen battle tower/frontier. (Saw a couple in the emerald BF, but didn't even know it was possible in 4th gen games.) Check him out:
I would have been
soooooo mad if rng-abuse didnt mean i already had one.