Instead of coughing up the extra $$$ & labor and guessing, try doing one of the calculations to determine the size of the service. Once you get a little practice, the calculation does not take very long, Residential wiring can be a real cut-throat business & you could end up pricing yourself out of some jobs.
That said, I'd go with a 400 amp meter base & two 200 amp MCB panels mounted next to each other. As Straightedge pointed out, plenty of circuit availability.
Tom
