Credit Score Repair/Increase

I pulled all three of my reports and scores today. Here are the results:

Experian: 546

Equifax: 562

Transunion: 524


I currently have 4 accounts in collections:

Beacon Services: $630 (sending Pay for Delete letter on Friday) Anyone have any luck with this company or with Pay for Deletes? If they agree, I will send the payment in full.)

Capital Accounts: $485 (sending Pay for Delete letter on Friday) Anyone have any luck with this company or with Pay for Deletes? If they agree, I will send the payment in full.)

Cavalry Portfolio Services: $1845 (same as the above, sending PFD on Friday) Any advice on this company?

Midstate Collection Services: $331 (again, same as above, sending PFD on Friday)


Will having this items "Paid for Delete" off my report help raise my scores, and do these companies actually do this?

If the company refuses the Pay for Delete, will it be better to save myself some cash and "settle" with the company, or go ahead and pay it in full?

Will a "Paid" collection account be better on my credit file than a "settled for less than the original amount owed" account?

Thanks for all of your help! I know that paying off this $3300 in collection accounts will help somewhat, but I'd like to help my credit score as much as possible!