750 Eddy Carb issues

You can't adjust properly the idle mix with the throttles open.
You need to check the fuel level. You can set the floats dry, but checks IMO should be done wet whenever possible.
Looking at the plugs will give you an idea of how the burn went down and if its was excessively rich or lean.
If the mix screws aren't responsive, then that tells a lot.

The fact the engine speed had to be increased alone doesn't reveal if its timing or not, but certainly leaves the possibility open. Need the timing at least in the correct ballpark since it works hand in glove with the fuel mix and rpm. Mechanical timing around 2000 rpm should be around 24* BTC. On a stock distributor that will probably put it around 5 - 12* BTC at 1000 rpm. The 5* or less initial was for early smog and coupled with a lean idle (14.2:1). Since you're using an Eddy I'll assume thats not your situation. Initial of 10 - 15* would work best. (if its the stock emissions distributor, a put some more tension on the primary spring so it doesn't move out too fast)