If your starting point is Bella Bella, and your goal is to avoid open waters and strong winds, then you'll do better to hang out in the northern Hakai area, within Queens Sound where you can hop from island to island across short distances. Heading north to Laredo Inlet would require you to cross Milbanke Sound and Laredo Sound, which are longer crossings.
If you're interested in Laredo Inlet, and Princess Royal Island more generally, then you might have an easier time to start in Klemtu rather than Bella. Starting in Klemtu, you'd spare yourself the crossing of Seaforth Channel and Milbanke Sound, and reduce your crossing of Laredo Sound.
I also think a canoe might struggle to make it from Bella to Laredo Inlet and back in ten days, particularly if you are going all the way to the head of the inlet. It would be much easier from Klemtu.
Forced to choose between Hakai and Princess Royal, I would choose Hakai. The islands in Queens Sound, Cultus Sound, and Kildidt Sound offer some of the most scenic kayaking (or canoeing) on the coast. Princess Royal consists mostly of long channels and inlets. Mid-August is too early for the salmon run, so your chances to see a spirit bear on Princess Royal are lower than your chances to see a wolf in the Goose Islands. Also, Hakai opens up more possibilities for a loop route rather than an out-and-back.