Will find a heap if info here on needle size etc. https://advrider.com/f/threads/crf1000l-spring-and-valving-data-base.1363798/ I wouldn't sweat spring rubbing in lower leg. Springs are smooth and have plenty of lube. If your getting shavings off spring or leg, there is something wrong. Even when ano wore in my original tubes, oil was stained but not too bad. Idea with bush to sit flush too outer tube is a good idea, but wouldn't over think the spring cause real issues.