High tack means it sticks well but also means you might not be able to readjust its position. Low tack means it is not very sticky, which makes it harder to hold in place, but you will have a lot of time adjusting placement.
Backing refers to the underside of your carpet, which is what ends up being in contact with your rug glue
. Depending on the material of your carpet backing, you may need a different adhesive. The best glue for carpet to wood is not necessarily the best glue for marine carpet to aluminum.
The type of surface is also necessary to note down. In the same way that we have to make sure the glue we use sticks to the backing, the surface type also needs to be considered.