So I had a couple of question while I was building last night about the Y-Axis. 1. What does smooth mean? I watched the youtube video about what a smooth y axis looks like, and if I move the carriage forward and back fast like in the video it feels fine. However, if I move the carriage slowly it feels a bit more choppy or "sandy." so I was wondering if I should be working to get it smoother. 2. One of the steps for the y-axis has you measure from the front of the big box too the the front of the x-axis rod. In the instructions it says both of these measurements should be the same for each side. Well I am using a pair of calipers and the difference is around 1mm. Is that close enough, or do they have to be exact? Thanks for the help!