First, congrats on your efforts, it's tough working on your credit.
It depends on when the charge-offs were and if there was a balance reported as well as the limit. Charge-offs report as a revolving balance most of the time, so if yours did, and there was a balance over the card's limit (like 9 times out of 10 it is on a charge-off) then you will get some score improvement just from having the utilization decreased. If the charge-offs were within the past 24 months, then the removal of the negative information from the reports should also result in a score increase. However, one factor in your score is the AAoA (Average Age of Accounts) so if there is very minimal credit history and the 3 charge-offs had a lot of "months reported", then the AAoA will be reduced and that hurts scores. As soon as the charge-offs are removed from each of the credit bureaus then the corresponding score will change - as in that same day. You can subscribe to a credit monitoring service like TrueCredit.com to get alerts when it happens.
From what you have said, "only remaining late payment is from 30 months ago", I suspect you will get a score increase, but depending on the variables above will determine how much of a score increase will happen.