1) After you 2) Approval 3) Green light 4) Knock yourself out 5) Like a tiebreaking run 6) Okay 
Go-ahead is British slang for forward thinking, progressive.
[v] - continue
A positive response to a query that assigns an article to you.
plow ahead verb proceed (with a plan of action); `He went ahead with the project`
permission or a signal to proceed: They got the go-ahead on the construction work. · a sandal held on the foot by a strap between the big toe and the next toe.