Is one booth enough for 200 guests

For up to about 150 guests, comfortably yes.

Past 150, the deciding factor is print speed rather than the booth itself. The Canon takes roughly 45 seconds a print; the DNP takes about 8. At 45 seconds a queue forms late in the night and people drift away from it.

That is why most 200-guest weddings book the Pro Prints tier. It is the same booth — the printer is the difference.