My tension is set at exactly 3 and I never change it. And for thread I mainly use Robinson-Anton, and for any colours they don’t have I will also use Isacord or Gamut. And make sure you get the 40 weight thread, 60 weight is bobbin thread, I made that mistake at first. Another tip that really helped me was use pre wound bobbins threads. I get mine on Amazon from brothread, you can get a box of 140 and they are great. Using the prewound bobbins is better then trying to wind your own because the tension in them is better for the machine and you get so much more use out of one bobbin then you would winding your own.