Do you love big bluegill?
Just stick with the popper about an hour before sunset to an hour after sunset. You won't need a dropper
And there you have it - tie the fly to the hook bend with an improved clinch knot. This keeps the dropper line tight to the popper's hook and away from the "works."
Often the plan is to tie the fly to the poppers eye, or on a dropper blood loop out front. Eventually, this method tangles the whole works and you get frustrated.
But tied to the hook itself with the rigid clinch knot and 4# test line, the fly rides in the back of the bus. I would also use a longish dropper line - something around 18"-24".
As far as I know, the sort of fly you use is important, too. You want a wet nymph style. This sinking fly will ride below the popper, catching the attention of the larger bluegill drawn to all the commotion caused by the popper. The popper itself then acts as a strike indicator.
My brother in law was a real "brim slugger" using this method back in the day. I just ordered a bunch of poppers myself for this.