With Robert above. If you are using an Electric Pump without a fuel-return-line, the pressure may be creeping up and overpowering the needle-seat.
I had to upgrade to a Return-line and By-Pass regulator on my Charger, when I added an electric pump for that very reason.
Could also be that you need "better-quality" or "different type" (like titanium or steel needle) needle-seats.
The "Bent" float situation could be a possibility too.
Around two weeks ago, on my Holley-carb'd CJ-5 Jeep, I had a similar flooding problem. Replaced the needle/seat, and it was still flooding.
Perplexed, I eventually discovered a disintegrated partial O-ring, in the needle/seat port, that intermittently blocked the needle/seat in the open position. Fished it out, and problem solved.
Still, my best guess is the Dead-Head/Fuel-Pressure creep issue.
BTW: I live right next to Ontario, California where that Carb Shop Robert mentioned is located. Not sure if they are still in business or not. My guess is Yes, but would need to look them up on the internet to verify.