The turns out on the idle screws is not too important. That's just fine tuning info. Something to take note of. If there is no or little response to turning mixture screws - that's useful for analysing what's going on. Turn them in and the engine should sumble and then more and it should die. (When throttle is at slow idle).
Fuel level - according to the the info on the Holleys wensite for that carb, there are fuel bowl sight plugs. Remove those to check the wet fuel level. If fuel pours out - float level is too high. If its dribbles out, the primary is about correct. Secondary I prefer keep a fraction under the plug in most cases.
Since your struggling with getting a steady idle, check the level with engine off.
