Sorry, proportional is the only fair mining method. A share is a share, no matter when it is submitted.
Why do you pay them differently then?
Anyways, at least you give a bit of challenge...
By the way, real pool DDoSing is done differently, but I won't give any hints here, because THAT would really hurt your pool I guess.
Paid differently? Not sure i follow, every share is worth the same. The other payout methods pay people differently....
Obviously its not a ddos, but it fits the definition spare the ill intent. Hence the quotes.