When should the tasmee and tahmeed be recited?

Q: I was always of the impression that the muqtadee should recite tahmeed in qaumah after the imaam completes reciting tasmee. However, I was lately informed by certain Ulama that the muqtadee should recite tahmeed at the same time that the imaam recites tasmee. I would like to know whether this is correct? I also wish to know whether all my past salaah are valid since I have always been reciting tahmeed in qaumah after the imaam completed reciting tasmee.

Disposing of interest money

Q: How should interest money be disposed of?

1. Is tamleek (passing of ownership) necessary i.e. does it have to be given to an individual person or can it be given to madaaris or for digging of wells, etc.?

2. Can it be given to non Muslims?

3. How poor must a person be to give him interest money?

4. Can interest money be used to pay tax, fines, bank charges, etc.?

5. If a person has bank accounts at multiple banks, does he have to withdraw the interest from each bank separately or can he just give the amount in sadaqah from his cash on hand?

6. If a person is in debt, can he be given interest to help him settle his debts?

7. Is interest money regarded as dirty wealth for the recipient?