The amount very much depends on a lot of factors, including but not limited to things like your spouse's income, financial situation, whether there's a child (and who the child is with) etc! Whether it's a monthly or one-time payment, it probably have to be discussed with the lawyers to come out with a mutually agreeable decision. If you do go ahead with a monthly payment and everything is settled by law, he is obliged to pay it to you - if he doesn't, you can go to the family court (I think, not so sure about exactly where) and make a court order for it.
actually the purpose of asking for monthly alimony is because if he ever becomes super rich, I think you can be entitled to ask for some money also. Not sure about one time lumpsum payment.
I believe this is truly dependent on the amount you spouse is currently earning. As about the immediate payout or monthly payouts, that's something that is dependent on the settlement.
That's depending on the settlement. I believe with the right laywer and bid of settlement, you can get whatever it is you require provided that it's justifiable.