Downsize your yarn and your hook. Have a look on the internet - there are plenty of sites that compare yarn and let you know what yarns are the equivalent of discontinued yars. Some even have pictures of the width of the yarns so that you can measure the yarns that you might like to use against the originals. These sites are really helpful if you want to downsize or use a yarn in you stash.
then, of course, you have to swatch..............:(
Cotton yarn is a great choice for making toys because it’s durable, holds its shape well, and doesn’t fuzz easily with handling. It creates a smooth, defined stitch, which is ideal for amigurumi or detailed patterns. Cotton is also washable, which is a big plus for toys that may get dirty or go to children. However, it has very little stretch, so tight stitching can be tough on the hands—using a comfortable hook or needle size helps. Overall, it’s a practical, long-lasting option that gives toys a clean and polished look.
the crochet hook size is very important I use thin cotton yarn with zero crochet hook this will make it small off course done by sc stitch , hope this was helpful and enjoy :)