Endless cogs do fit tightly. If your hub has any raised notches from previous use they will need to be filed down. I have not put an Endless on a Hope hub, but I ran into this problem when trying to put one on my old Machine Tech hub. A little filing on the notches and it went on. It was still tight, but it did go.
FWIW, they even fit tightly on a steel Shimano cassette body.