CosmicCat
TF Ace
Thank your for the suggestions, @plastikman 🫡 Really appreciate it. I'll ponder more about it.Since, it is impossible to know the actual heat load in your room, and also the fact that ACs are available as either 1.0 ton or 1.5 ton; only empirical thumb rules have to be relied upon.
Most of the AC manufacturers use the volume / area method which would suggest around 1.095 ton for your 120 sq ft room.
The conundrum is that 1 ton AC may work just fine for your room but since you have sunlight coming into the room, the room maybe getting warm as well so hopefully 1 Ton will suffice.
As humidity is high in your vicinity, a lesser tonnage ac will run longer and dehumidify more.
So, if I were to decide for myself, I would get the 1 ton AC but with 5star rating (preferably inverter type) as it may run longer and dehumidify well but consume more power. On the otherhand if you choose to go for a 1.5 ton AC may not dehumidify well. But in that case you can always get a portable dehumidifier.
So, as you can see there is no straight forward answer to your question.