Jon,
From the water
Start climbing on the front side of the board. That side is easier to get weight over (as it is blunt) and will be a shorter reach to the gunwale due to the RS Aero narrowing forward.
You are unlikely to climb on board before the boat comes up as the rig is so light so you need to reach up to the gunwale or control line tales (acting as capsize lines) below, to finish pulling the boat upright.
You should be pulling the aft end of the control lines, where the boat is widest amidships.
Amidships
The rib under the cockpit edge is the 'grab rail' and your 1st pull should be on that.
The 2nd grip/pull is onto the toe strap. Keep your weight low and kick your legs in time with your pull.
At 78kg I have never felt the need to pull in on the mainsheet to balance against the sail. Going for the transom instead would be no more effort than that.
Transom
Climb in the windward side of the transom.
As you go to the transom make sure the boat is not at a too broad an angle. If it is too broad it will be more likely to bear away as you climb in the windward side of the transom. The boat is so light that it is very easily manipulated whilst in the water.
Throw the tiller extension out of the way and do not use the tiller to climb in with.
The 1st grip/pull is on the honeycomb flaps, they are strong enough. You can either push your body up vertically or horizontally as you choose. The flaps will come down towards the water level as you push down.
2nd grip/pull is on the toe strap.
Again a big kick of the legs at key moment will assist the arms.
I have seen an 81kg sailor climb in amid ships without any wind to balance against.
I have seen 93kg fail to climb in amidships in no wind, but then climb in the transom very easily.
I have heard of 98kg climb in amidships when there was breeze to balance against.
Everyone has to find where their personal side/transom preference is. This depends on weight, agility, technique and wind strength and the only way to properly assess this is on your first capsize.
Let me know if anything is unclear and when you have some support give it another go.