Equity funding approach

Hi everyone! I’d like to ask your opinion on how you would structure an equity funding round for an M&A roll-up. Eg there is a project to acquire say 10 companies in a sector. Do you:

a) Raise money for each acquisition as needed (can be done after each acquisition completes as needed, but then likely a lot of time spent fundraising), or

b) Raise a larger sum upfront for the whole project (but then how do you come to a fair valuation) ?

Would love to hear what anyone has seen in the market for this kind of scenario. In my particular case, 1 acquisition done already, another one should be closing v soon and plan to acquire more as part of a (UK-based) logistics sector roll-up.