August is going to be a super slow and mellow ride. Peak flow is mid June.
River Runners, Sage, and AVA are all quality guides.
Also, if you can book the earliest morning slot. Mid August sun in an inflatable is like being in an oven on high broil.
If you're going to be staying in BV, you may just hit up the water park section of the river if you have the gear. Numbers is already hella mellow so it's going to be a lot of chilling with not much action. When we go home this time of year, we usually go to the park section this far past peak flow because it's a little more attention grabbing for youngsters and not nearly as hot.