The working temperature should really be around 18c, I appreciate that’s not easily achievable in tropical countries unless you have air con! I live in a cold country and still find modelling chocolate becomes soft while working it. Here’s what I do.
Work in a cool room, if you have air con that would be ideal, if not a fan to circulate the air can help. It’s not quite so affective in very hot climates, some ventilation is better than non!
Keep several cookie sheet in the fridge and use these as portable cold work surfaces. Bear in mind that when the pans come out of the fridge they will have condensation forming once the hot air hits them. Wipe the wet off with paper towel and cover with parchment paper to create a barrier beween the paste and any more condensation. I also have a couple of marble slabs to work on. I make them both very cold, work on one until it starts to warm up and rotate with the other making sure to wipe off condensation. A bowl of ice and picnic ice blocks to cool hands on are a must! I guess you don’t have a coolest time of day? if you do have a time of day when the temperature is cooler, that is the best time to get as much work done as possible. Oh yes, if the paste gets really, really soft, knead in a little melted chocolate and leave to harden, not in the fridge. Re knead without over handling on a sprinkling of icing sugar.
Works for me but I do live in a cold climate. Hope it helps you.
roz