It sounds like you've got everything set up nicely for your baby’s comfort. A 1 tog sleeping bag is indeed typically recommended for a nursery maintained at around 20-22°C (68-72°F). This should provide a good balance between warmth and breathability, helping to ensure your baby has a cozy night's sleep.
One practical tip is to keep an eye on your baby's hands and neck—they can be good indicators of how comfortable your baby is during the night. If their neck is warm and dry, that’s generally a good sign. If their hands feel a bit cooler, it’s usually nothing to worry about, as it’s quite common for babies.
Some parents also opt for layering, like using a light vest or pajamas under the sleeping bag, which can make it easier to adjust if the temperature shifts slightly.
If you’re still unsure or if your baby seems uncomfortable, you could also try using a room thermometer to keep a close watch on the nursery temperature, and adjust accordingly. Experience-wise, plenty of parents find that it might take a couple of nights to see what works best, so don’t hesitate to make small changes as needed.
Have others in this discussion found particular sleepwear combinations that work well in similar temperatures?