It's really a crapshoot right now to give you advice either way. The snowpack is significantly above average, and the forecast is for the summer to be rainy, but things have just got really hot and the snow is melting fast. As Andy said releases are cut off middle of August, so the flows after that really depend on the weather for the next 60 days or so....
I wouldn't personally take a group of framed rafts down the Milk Run at flows less than 500-600 on the Nathrop gauge. If flows are lower than that, look at going downstream. Salida East to Rincon is a good alternative.