If you have fuel leaking out the left air filter your float is sticking open or is adjusted wrong or fuel soaked.
The only way gas leak out of a carb is through the float valve. Pull your carbs, clean them check the floats for fuel soaked and ajustments.
Leo
It's too bad you didn't test the coils before getting new ones.
At first I thought your problem was the filter inside the tank. I would definitely remove that and clean that anyway. Especially chrome spray paint?
The float needle valve - not closing - is allowing it to flood over. Take carbs apart and from square one make sure floats are adjusted to proper height. Also (like a problem I had) after adjusting float heights hold carbs upright then turn upside down making sure the floats move smoothly to close the needle without catching or sticking before moving against the needle. That would cause flooding.
The spark plug on the flooding side is just fouling up maybe and overrevving it might get it to spark, like you were doing.