Dry settings call for 1/2" Primary, 3/4" secondary. on the 2804-2805. Recommendation was also to turn the needle and seat back a couple flats off that setting. Then keep them below the window being they are mounted backwards.
You need to balance these settings. If they are too high they will flood at idle on level ground and at any incline. If they are too low, you run the risk of running dry under running conditions.
If that happens, the engine will violently back fire through the carbs. Often that will be so violent that the choke plate retaining rod will be bent or the choke will completely will get blown out of the carb.
It's like a hand grenade going off right in the intake manifold.
I find that the top of the floats being set just at the bottom of the sight port is about right.
At one time I had gone back and set the carbs dry, off of the engine, exactly according to the Holley instructions. Upon reinstalling the carbs, they completely flooded the engine. Flooded in the sense that I heard 'God's instructions,"Noah, build an arc."
Pity me. I have two engines running 2x4 set ups. They are not easy to get just right. Webers are child's play by comparison.
Oh. I'd also STRONGLY recommend that you change the floats to the solid Nytrofil plastic ones. DON'T ask me why. You don't want to know why.