It is useful in attempting to understand Grand Crosses for you to first get a good grasp of T-squares. This is because a Grand Cross is essentially a set of 4 t-squares, with the focus needing to be on the apex planet of the t-square, with a view to eventually bringing one's focus to the opposing sign & house to the apex planet.
Given that a t-square is considered to be a stress placement, a set of 4 t-squares would appear to be 4X as stressful. This may or may not be the case. With a group of (at the minimum) 4X squares, usually all in the same modality (i.e. either cardinal, mutable or fixed) this usually provides a focus for the person to drive themselves. T-squares and grand crosses - although considered stress placements - can be an enormous driving force in a person's life. A lot depends upon the modality, as well as the planets and houses involved. A lot also depends upon how freely the person feels able to express themslves as they know they must.
I have had a quick look through the Search facility on this forum, and there is not much written about Grand Crosses. This small thread may help you:
Do not stress yourself over your daughters' grand crosses. I'm sure that they actually `know' how they can best use them and handle them, regardless of the age your children are. Children being born these days are very very wise.