Tuning Edelbrock Carb w/ help of Wideband - Suggestions?

Greetings,
I picked up a wideband oxygen sensor a few months back on eBay and installed it on my '69. I have the Edelbrock 1405 w/ electric choke. I have the needle/spring kit for it and have been doing some 'seat of the pants' tuning for a couple of years now.
Well come to find out the thing was running incredibly rich. 12:1 at cruise and up to 10:1 when I accelerated. The meter never even touched 14... Part of it was my fault because for some reason I thought it needed more fuel so I put smaller needles in the primaries.
I changed it back to nominal and the AF ration improved a bit but not much. I then went one step leaner for both cruise and power mode. This helped and the full throttle mix is around 13 as it should be.
My issue is that before, when I would 'goose' the throttle, the engine would react immediately but now it's a lot more subtle. I don't see any mixture leaning or anything else that would indicate I need more accelerator pump action. I'm not sure what else to look for.

Has anyone used a wideband to tune an Edelbrock carbed Mustang similar to mine that can offer any suggestions?

My combo:
302 +0.30
Edelbrock Performer RPM cam, intake, 600 cfm carb
hand ported stock heads w/ screw in studs, roller rockers
long tube headers
pertronix

Thanks for the replies.

Rapid,
Does the manifold vacuum keep the rods 'sucked down' into the jets until it drops enough for the springs to overcome the vacuum? Would I want a stiffer spring - one that pushes up the rod sooner (richer) or a weaker spring that leaves it down longer (leaner)?

I could be wrong about the operation of the springs...

The accelerator pump rod is in the middle (of 3) holes. I can try it in the closest one (fastest onset of fuel) to cure the perception of bog - after I check the timing.

My carb wasn't new but I do have all the paperwork. I'll start from the beginning and go through it. I had an hour or so the other day and the new wideband hooked up so I thought I'd have a go at it. The way the weather has been lately, it may have to wait until spring for me to do any more tuning.
Thanks.