Just when its getting juicy I am having trouble getting on the internet! damn
To address a few earlier queries. I think the GD tarot does start at 0 Aries - the 'first' tarot card is there. 0 Leo is the start of their zodiac - the card attributed there is not the first tarot card. As stated 7 does not go into 12 evenly so there is an extra planet attribution and it is Mars. GD says that the extra mars is needed so the the fiery energy can bring us out of the long cold of winter ???????? Rubbish IMO (see my other post where I discuss this and other ;'strange GD issues) - ceratinly does not make sense to those of us 'down here' (south hemisphere)
However it makes good sense to start a zodiac at 0 Leo (or close to it) because of Regulus, Regulus does not move, like the equinoctal point does, its easy to find Regulus, not so easy to find the equinoctal point and Regulus is VERY close to the ecliptic so it is a 'natural' marker.
Its also used in modern space navigation. NASA had to use a different fixed point than that used on a star map, The equnoctal point is only relavant from earth and no use when one is zooming around 'out there' so they use Regulus ... for similar reasons.
At one time the Equinoctal point would have been at Regulus, that time can be found with a computer program (that I dont have access to anymore) - that date might prove interesting.