I just got my order today and Ive found the right sand paper to make the rounded tip just like the store bought light sabers. I used Waterproof Sand Paper #400 it says on the back. Its real fine and does an amazing job on these things!
These are the best 2 shots I could get with my camera, so I hope you can see the rounded tip on the bottom one. It was a broken saber I cut for a padawan. Compared to an original one, not too bad.