Yes, the silicone is very thick and viscous and it does require patience to get it out of the bottle. I would not try to fill up the cup more than 1/3 of the way, at least initially, since it will take time to remove the excess. I purchased a turkey bastor syringe and used it to extract a good portion of the silicone from the bottle and then injected the stuff into the cup. It took awhile, but it worked. I stopped at about 1/3 full and my WTT sounds fine.
You may want to try contacting Mike Pranka the distributor about obtaining more silicone. Good luck and happy listening.