With the gauge at Ada at 7.6 feet, the Grand River is in mint condition. At this level, the weedlines are just sub-surface and there is a ton of baitfish in them. So target these lines using floating lines and swimflies. By switching to a floating line, it will keep your fly swimming at the surface or just below it, and out of the weeds.
The topwater game has definitely slowed down. Quite frankly, the past few trips we haven't even thrown a boogle bug or terrestrial.
It has been a lower-light bite on the Grand, with mornings and evenings producing the best results and the better quality fish. If you have to fish during the day, use a heavier multi-density line like a I/S3/S5 on a weighted crayfish pattern in the deeper pools and runs. Mix up the strip cadence and at times just dead drift the fly or swing it.