How much time must elapse between closing a card and opening the same card in order to receive the full miles promised by the new card?

What is the approximate average hit that we take on each credit pull? 5 points? 10? I know this is impossible to answer precisely, but would love to hear from people with specific experiences.

Is it okay to apply for 5-6 cards within a short period of time even if the bank offering the card is the same but the airline is different? For example, would opening a Chase SWA card and a Chase CO card simultaneously render you ineligible for bonus miles on one or the other?

Thanks all!