All you need is :
Whip the cream adding half the sugar and then cool it in the fridge.
Do not over mix.
Dip each lady finger into the coffee and rum mixture then line into a rectangle baking tray, it is much easy to remove if your tray is a square or rectangle shape.
You can make 2/3 layers. We made just 2 layers.
Then cover with cling wrap and chill for 6/8 hrs.