You always will have better and quicker results cross direction sanding, unless you are laying down a satin type directional finish. Because you lay down a stria pattern then remove it cross directionally, then lay down another and remove it.

I hand sand 10 – 20 strokes in one direction, then sand 90 degrees to the stria you just laid down, when you can. Circles will leave circular scratches that are hard to remove, and I feel I have better control directionally.

Once you remove all you staining, rust or pitting, then you want to lay an even stria pattern that will be removed by the next grit. You can feel when the paper stops cutting, replace it. Paper is cheap.

Often folks think a shiny 1k finish is stria free, but look at it at 100 or 400X and you will see the scratches, even high grit polish leaves stria.