We need a bit of a frost to drop the water temperature.
A few pointers:
The wall is tidal and needs to be fished on slack tides.
On the bigger tides the best you’ll get will be about 1 hour before and 2 hours after low or high water.
You will still be able to fish but the catch rate drops as the tide will sweep your line out of the channel.
If you are travelling down from the East Coast and are making a day of it I would look at fishing Monkstown in day light and hitting the Youghal beaches, in darkness, on the way home.
The weather (rain) plays a big part in fishing the dropping tides. If the river is in flood then no weight will hold bottom as you have to compete with the ebb plus the fresh water that has been held back by the flooding tide.
Casting into the channel you are fishing into about 60/70 feet of water. As you reel in you hit the rocks about 80yds out they do not take prisoners what they catch they devour.
If the big cod (3lb+)
are about your best rig will be a pulley rig and a 2/0 hook. When you have a big fish on just reel as fast as you can as the fish will dive to the rocks. If you do get snagged give a bit of slack line and wait often the fish will head back to the channel and pull out of the snag. 
I’m inclined to using about 30ft of shock leader when fishing there over low water. When you get a fish to the wall you will have the shock leader onto the spool which let you pull the fish up by hand.
For the smaller cod and whiting, if they turn up, a 2 hook clipdown and a size 1 hook will do fine. The whiting will take mackerel or lug but will be quite happy to enjoy your crab as well.
The biggest drawback is other anglers crossing you
and it will happen all day once the run starts.If you do see an angler pulling you in then start reeling as fast as you can as he will only pull you in to the rocks and there is a very good chance that you will lose your gear.
Crab is the best bait by a mile for cod. If they are on the feed just add a lug to the used bit of crab.
A good distance cast will get the bigger fish
IMPORTANT NOTES:
PLEASE TAKE YOUR RUBBISH HOME WITH YOU.
The footpath is a busy area and is used by a lot by people out for their bit of exercise so be polite
make sure your rod or rod stand do not obstruct the path. If you want to use a rod stand put the legs over the railings.Sea weed left on the path way is a big problem. In wet weather the stuff is like walking on ice and could be hazardous to elderly people using the area.
Dogs and hooks do not get on so do not let baited hooks lying around. Personally I always explain this to dog owners and I am always given a welcome response.
Update and comments here: http://www.sea-angling-ireland.org/bull ... =1&t=44327
http://goo.gl/maps/HIucN The grassy patch.
This spot can get quite muddy under foot and is a graveyard for tackle. You will need to reel in here pretty fast
http://goo.gl/maps/YmyTk Park here. If you fish opposite there you WILL have to move when I arrive as this is my spot.
http://goo.gl/maps/aM3bj More parking here and cleaner ground in front of you for fishing.
Enjoy it if I missed anything I’ll add it as a PS here
