Shelly can get very busy and crowded during holiday season. Never launched there.
Have not been out at any of the other two for quite a while as we now have a cottage in Hibberdene and I am a member there and launch from there.
I can give some pointers from what I can remember if it may help.
December can have up and down conditions so best to check on these carefully before launching.
Both Glenmore and Port Edward is best launched when you have a Swell from South. Both get nasty with N or especially NE.
Both can have very loose/soft sand so deflate your tyres accordingly.
As with many launch sites on the South coast, turning options are very limited and launching at low tide can make things a lot more tricky.
Glenmore has a submerged rock which is visible most of the time. You can hang back behind this rock as it gives you protection from the south swell and this gives you enough time to time your launch. When you decide to go the normal line is NE to start with, making sure you miss the submerged rock by a wide margin, 25-30 meters,(I cant remember but I think they call it whale or submarine rock)
as soon as you have past the rock and enter the surf swing right to the horizon and head straight out. You will have to face anything head on if need be from there. Turning left(north) and trying to run the gulley could be fatal as there is always a sandbank and no space to turn. Rather face and punch if need be after committing.
Just make sure you pass the mentioned submerged rock on the way in. Been a long time since I been out there, a lot may have changed.
Port Edward, has the famous gearbox rock, not easy to see and best to make 100% sure where it is before you try launch here. As mentioned with a swell from South, quite nice. NE nasty. You have the rocks on the right and then a prominent rock in front of you. This rock provides shelter from the swell if it is from South. Gearbox rock is basically inline with this but further north. Two lines are used here. Some of the experienced locals launch between gearbox rock and the big rock in front of you that you can shelter behind while timing the launch. You can launch quite close to the left side of this rock(with the rock on your right).This is the shortest route to get out, however you need to be prepared to face and punch if needed as once you have committed on this line you cannot turn. I have seen locals even in big surf prefer this line. The other line is again N from behind this shelter rock passing gearbox rock and once well clear of it turn right again to the horizon and then out. This is the longer route and not recommended if the swell is up and you are not familiar with the launch.
As far as I remember there are two poles(white?) on the hill behind the beach, you line them up to get the line. Come in until you are past gearbox rock and then turn left into the protected area behind the rock you used for shelter and beach.
Some of this may have changed in the meantime so it is best to check with the locals. You may also want to phone the respective clubs from the different launch sites and then ask them with regards to launching etc. as there may be boat launch restrictions for the different sites. At my club for instance the limit is 20 boats per day.
Best advice I can give is to go to where you want to launch, sit there and watch the locals launch, chat to them and get the latest with regard to best lines to use and what the do's and don't's are. Conditions can change rapidly from day to day, more so in Summer.
Most of all if you are not comfortable don't launch.
