I think the Thoroseal instruction are to apply a second coat within 24 hours. That is pretty tough stuff and not like a paint product.
Often, an acrylic added to the Thoroseal to get some better bonding to the base material. This is when you follow the mixing instructions, including to short wait to allow the mix to absorb water and "fatten up" before the finising water addition.
One problem is that Thoroseal becomes very resistant to bonding and does not absorb much water after it is aged and even repels water quite well.
The best suggesting I have is to mist the wall just before applying the Thoroseal and use an acrylic added to the mixing water for getting the dry Thoroseal ready for application.
I think one of the additives suggested was Acryl 60 when I used it.
Thoroseal is not like a paint-type material like DryLock.
If you have some pre-mixed Thoroseal, good luck.