I have sealed up weepy, porous tires with good success using Continental’s recommended method of rubbing the sealant into the full surface area on the inside of the tire. It has worked for me using regular Stan’s on multiple tire brands. Continentals are notoriously porous, which is likely why they recommend doing this.
I had an OEM Maxxis DHR II that was so porous that the sidewalls were peppered with Stan’s boogers and it wouldn’t hold air overnight. Rubbing some Stan’s into the sidewalls using a paper towel solved the problem.
Continental’s tubeless install video: https://youtube.com/watch?v=1HfULR0PnZE