Cut the paper block
My favorite watercolor paper comes on a block. It’s bound on all four sides with a small opening that allows you to slip in a knife and cut the paper off the block. The blocks I use consist of a thick backer board and 20 sheets of 140 lb cold-pressed paper.
The advantage of a block is that the top 18 sheets remain stable and the paintings dry very flat. I have had the experience that the last two bottom sheets are less stable if they are highly saturated with water and can pull away from the backing, but normally this is not the case.
I painted an entire children’s book on two blocks. It was a small investment, but buying the blocks of paper helped me to commit to my vision of producing my original watercolor paintings for my story.
It all begins with a block of paper. I bought mine at my local art store, Dakota Art in Bellingham. But if you don’t live nearby, here is an affiliate link for the same paper I used. Arches through Dick Blick