Lacunosa watering/care

Hi!

I've had this hoya for a few weeks now and it's beautiful! I cannot seem to figure out the watering though... some of her leaves are soft and some are very firm. She's in the same nursery pot I got it in and the substrate is probably a mix of coir and soil. It's in a bay window that gets some south sun. I just can't really tell what it prefers.

Any advice appreciated!!