Depending on the client ask, and depending on how big the project is, I think everyone needs the space and time to be able to think through a problem, and be able to sit with a problem. I'm always a big fan of people doing their homework, doing their individual contribution separately when they've been briefed on a problem, then bringing it to the table, and then making new recombinations of ideas, and talking through them as a group.
Depending on what that teams cadence is, it'll definitely drive how many meetings you have with the client. I also think that launch dates play a critical role when something has to go live, but I'm also not a fan of keeping clients in the dark for the big reveal and having them be shocked. I think having some semblance of experimentation up front helps a ton, and bringing the clients along for that ride, giving them some initial ideas, or allocating the budget a certain way where you can experiment the beginning and work up to what that bigger campaign idea will ultimately be.