Wideband

ir3333 said
This is where some find the Edelbrock carb is a good fit.Using their guide it is very easy to tune each circuit seperately.
Having said that i found it impossible to clean up the idle on larger cammed engines...they just seem to create too much uburnt fuel at lower rpms.
...maybe it's me?

It's not just you - lots of people do. It gets easier as you understand what and why.
In the situation here, the OP is not going to be able to get a decently rich mix at idle to fire cleanly unless he changes the timing. Its not just the amount of fuel allowed in, its also how much heat is available in the chamber to convert the fuel droplets into a gas (think vapor) that will burn. Not enough heat, the burn will be incomplete. With locked timing, may be able to get it a little richer at idle, but I don't think he'll be able to get it into real sweet spot.
Other reasons it can be difficult Crackedback covered above.
Important thing to follow a strategy to understand what is going on.

crackedback said
Drive on a flat road and slowly increase your speed, start at 1500 and roll there, then go up to 1750, 2000 and so on. Observe the reading. There should be a point where the numbers drop.

You need to find the point on cruise where the main jets activate. Doing this will allow you to make adjustments to the correct circuit.