Seconds on the BWO thing, if it's overcast at lunchtime find a foam line or back-eddy in a hurry. Don't get all concerned with matching the hatch with a BWO fly. The appropriate sized Parachute Adams will catch any "D" redside during a mayfly hatch.
If you nymph during the day I would advise you to use a fairly stout leader, the trout really are not that line shy and you have a very very big chance of hooking a steelhead this time of year.
September/October on the "D" can be scary for trout nymphers.... :shocked:
Have fun!