A lot depends on what the object of your reading is - horoscope or astrological spreads are good for things like the year ahead - each card in the circle representing a month (possibly starting with this year's birthday) - they are also particularly good for a reading based on the areas of life covered by the houses - so the card for the 'seventh' gives an indication of partnerships and marriage. This does require you to have a working knowledge of the houses and the way that they are most frequently used - for example in practice the eighth house is read as the resources (money) of the marriage rather than as the house of death or the house dealing with sexuality. This is because its the second house from the seventh. The second house deals with material resources, and by extension the second house from any other house can be looked on as dealing with resources.
Whilst it is not essential at all for a 'house' reading, you might find that knowing the Ascendant of your querent gives a better result than basing it on the Sun sign. However if this isn't available then I would actually do a horoscope reading treating the Sun sign as the first house - so both Virgo and Libra would be read in the same way, though you might use a little knowledge of the signs to think about the different ways in which they would react in each area. So for example your Libra subject has Scorpio on the second House of material resources and would deal with these in a far more intense and secretive way than your Virgo subject who has Libra on the second.
If neither of these approaches is what you are looking for then you might consider a 'standard' spread instead.