Nobody can determine the weight of the soul. Even ants have a soul and what is its weight? Previously there were many animals of all types and its population was vast but now most of them are extinct and population decreased. Their souls are born as Humans now and hence population of human being increased and that of animals decreased but if you compare this with Satyug then the population must have been hardly 1% of what it is now.
A soul has to come back again and again till all its previous bad karmas are wiped out. Usually a soul comes back in the same family and even if it has to come back as a dog or cat etc. etc. it comes back to its own family. This is the general tendency. I read this in a book where the Lady, who lost her two sons in an accident, got all information from one of her son\'s soul through AUTOWRITING. The book is the Laws of the Spirit World. Both the parents of these 2 boys were alive. Father expired some 8/9 years back and recently the mother expired too.
Both the boys went straight to Level 2 up in the Heavens. There are 7 Levels with No. 7 being the lowest where souls who have sinned the maximum remain. This boy has told everything about the situation up there through Autowriting to his mother but he is not authorised to tell the future. He gave only what is wrong and what is right in HIS eyes. Then his mother would write it down in the book. Level 2 souls can go lower down to any level but they have wear special glasses as then they cannot see. It is darker in lower levels and they claimed to have seen even pastors, fake babas, sanyasis and those who enjoyed very high status in this world in the lowest levels.
I had to change my ID because I had to change my password several times and when the ID stopped accepted the changed password I had to change my Logging name.