I think that it depends on who is reading and how much they know the people in the querent's life. It is much easier for someone, say myself, to draw a card that has zodiac significance to me as a student of astrology than it might be to the querent....I can offer a description of the person based on what I know from the card's indication and what I feel...
For an example: I did a reading on Halloween with a young man that I had never met before. As his foundation I pulled a Q Cups. I got this warm, yummy cookies in the oven feeling and asked him what sign his mother was -- AQUARIUS. But I was to find out later that she is the hub of the emotionality in the family. So for me, Qcups was a definitive indication that his foundation, the force that would stabilize him is his mother, who by the way was very worried about him and loved him very much... but I digress.... she doesn't look like the picture on the card and she's not a water sign but she is an older female and embodies the characteristics of the card.
For readings that my one professional reader friend had done for me with Rider-Waite, I came up as the Q of wands... not surprisingly I have red hair and fair features with green eyes. But it might be interesting to note that I often get the Q of swords as well (due to my highly analytical nature) of the Rider-Waite deck. If you'll notice she has red hair as well though it's darker than the Q wands of the same.
I suppose that this is the long way of saying, you choose what feels right to you and your guides will use the appropriate cards to get the message through... pick a system and stick to it, eventually you'll find that they've got it down too and the lines to communication will be a little less muddled.
Crystelle