Ditto on Mudruck's RCBS case prep center, it is my favorite. Actually any of the automated chamfer tools by the posters or at the bare min. the standard size in/out chamfer tools by Redding, RCBS, Hornady, Lyman, etc. are easier to use than the smaller Lee tool.
Something to do with age, carpal something, and arithmetic fingers makes it tough to do repetitive motion with small tools.