Small hands - should I get a full-size or 3/4 size classical guitar?

I think you're making a mistake. Classical guitars are used primarily for playing classical music. If you're not interested in playing classical music there's no reason for you to get a classical guitar. Most fingerstyle players use a steel string flattop acoustic guitar although they tend to use an OM style with a slightly wider nut to allow better access to the strings. Those guitars also have the benefit of being more comfortable and having a more balanced tonal range.