Women's satr exposed in salaah
Q:
1. I now wear 2 khimars, 2 shalwars, 1 half-sleeve T-shirt underneath two kurtas, and a pair of gloves (and I try my best to tuck in the sleeves of the 2 kurtas into them) until the wrists because my clothes are thin and quite see-through. After wearing these clothes, I feel comfortable, Alhamdulillah, that the satr is not going to be seen.
My question now is that if a woman goes into sajdah and if she is wearing a see-through kurta (and no other shirt) and even though her khimar (which reaches almost until her knee cap when she is standing) still covers her body during sajdah by draping around it but does not cover the kurta itself such that if someone (like an angel or a jinn) were to watch her from below the ground, they would see the kurta uncovered by the khimar but someone standing on the ground could not see anything underneath the khimar at all. Does this invalidate the prayer?
2. If two limbs are exposed during Salaah, each less than a quarter of its whole area, how can a woman know if it invalidated her prayer? What is the length she can measure to?
3. If a woman wears shalwar (which kind of shows her figure but is not figure-hugging like tights), then is her Namaz valid?