First off, welcome to the Village Matthew. I’m a bit confused as Flying Dutchman does not make an FD UR #2. There are #1, #3, #5, #7, #9, and I think a #12. I am of the mind that you always, always use the highest tension as possible. I used DeWALT saws for over twenty years and have always set the tension as high as possible, including the smaller blades such as 0/2, and #1. I alway thought that the numbers on the tension lever were unnecessary. I’m sure there are scrollers that adjust their tension according to Wood type and thickness, but for me, it’s the highest tension as possible. You always want to hear a high “ping” when you pluck the blade, regardless of blade size.