2.3 running rich?

[BenzeneBear]

Hi, I have a 1979 ford fairmont country squire with the 2.3L lima. The car has been giving me a headache for a while now.

The engine never ran right, so i rebuilt the carb, changed the timing belt (it snapped when driving, bless non interference engines), plugs, wires, rotor, fuel filter...

But now i have a new problem. The car seems to run criminally rich.

During startup:
It runs on three cylinders, puffs white smoke and reeks of fuel.
After a minute or two the car almost dies (200 rpm idle, alternator light on, shaking), so i have to give it a bit of throttle, but after that warms up 'normally'. When i rev the car while its cold, the misfires gets worse until 2000 rpm when it clears out, it returns when letting of the throttle.

When warmed up:
The car shakes slightly when it idles, i think it misfires slightly and has very old engine mounts.

Now i can live with all of that for now, here is my true issue:

When driving, the exhaust smells of gas.
I also noticed it blows soot out the exhaust when revved, and has trouble starting when warm.
It also pops when letting my foot off the throttle.

My hypothesis is this: it runs way too rich. (though it does need the choke when cold, so that's weird).

Now the timing is set at around 10° BTDC (it idles worse when retarded any more).
When I configured the car after the carb rebuild i followed Thunderhead289's way of thinking:
square transfer slots, adjust timing to get idle speed right, vacuum canister to ported, then set highest vacuum.

Here is the problem:
The car won't idle with square transfer slots, so I opened them a bit more (it still has 0" of Hg at idle on ported).
But this is what i noticed: when idling fuel dribbles out of the main venturi (holley 5200 with mechanical secondary).
Could this be part of the problem? I think i opened the slots too much, but it won't run without them.

Vacuum at idle is about 10" of Hg, and the idle screw doesn't make much of a difference.

My assumption is that i have a vacuum leak, over adjusted on the transfer slots, so now it dribbles fuel out of the venturi at idle, and runs rich.

So i have a couple of questions for the pro's on this forum:

Could my assumption about the transfer slots be correct? The fuel bowl vent seems to have an electrical connection, could this be the problem?
AND
How would i make sure the egr doesn't cause a vacuum leak? I don't have a blanking plate, does anybody have some diagrams to show me what i would have to connect to where?

I'm sorry for the huge post, am I allowed to post multiple questions in one thread? The question in bold are most important.

I will attach pictures of my spark plugs and pcv hose, the dribbling venturi and idle readout can be seen here:
https://drive.google.com/drive/folde...MI?usp=sharing

Thanks in advance, vincent.