1. Anything more than C cup or higher hollow is the best choice, but anything lower than B cup is because there is not enough space to make it hollow.
2. Hollow breasts are air-filled boobs, not a TPE or gel. They are more realistic and extremely squishy. It is an amazing feeling to grab these breasts and watch them bounce back relentlessly. No added cost to upgrade. It is a good choice if you really like a pair of super-soft, light bouncy breasts. If you want a chubby sex doll with huge breasts, you can choose hollow breasts to decrease the weight. But if you’re overly obsessed with heavier breasts, this might not be the right choice for you.
Learn more about sex doll breast options from here!