I would be carefull on planning shore dives based on tidal exchange, we find that planing them based on current tables is a little more forgiving in Campbell River; for example, we can have a 2 foot tidal exchange and +/- 11 knot current exchange in Seymour narrows which means around 4-6 knott peak current in the Campbell River area.
Diving in 2-4 knott current is both fun and exhilerating, but knowing what sites to dive on what tides, makes the area a challenge for divers and charter operators alike.
On the 10th the current tables predict a -10.4 knott ebb going to a +9.3 knott flood (Seymour narrows). The slack will be short, if any, and may make a better drift dive - watch for upwellings at Whiskey point. A drift dive can be done by shore as there is an access road running along this side of Quadra, with road access to the shoreline in multiple places. Stop by one of the local shops, someone can show you a map.
I think you would be better to dive Campbell River on your return from Pt. Hardy on the 15/16th as the currents are down to -8 ebbs to +5.5 floods. These are ideal for drift diving in the area.
Have fun on your trip.