The problem with most pre-pastes is that the glue often needs to be adjusted. I do this for a living & the amount of adhesive varies widely That is why I won't use, or hire anyone that uses a water tray.
Pick up a quart of premixed wallcovering adhesive & add it to your water as needed. Different wall surfaces will vary.
If your walls are textured you'll want a fairly stiff mix. Hard to explain from here. Get a bit extra & experiment. You want 'slip & grip' . If the edges curl stiffen the mixture.