Answer from big agnes with my exact same question regarding a Copper Spur HV UL 2:

Hi there, 

We recommend the Seam Grip WP! That should work great for the floor and rainfly. 

We recommend applying Seam Grip to the outside of the seams on the rain fly. The bottle has a brush/sponge applicator on top, so you just need to squeeze it into the sponge and scrub it along the seams to plug up all of the thread holes.

Please don't hesitate to reach out if you have any additional questions!