hyperc10,with the restrictor in you should be able to still see down the carb and see the opening of the slide. You may have to tilt it in a good position but you will be able to see it. The opening at the largest point will be .5mm-1mm Both my B5's are right at about .75mm. Its a bout the thickness of a credit card or a thick guitar pick. I just checked my 2 B5's for those who still need help with this and my idle screws ar 1 full turn in from when the slide is closed. So slowly back out the idle screw until the carb slide is closed stop right when it is closed. The turn in 1 full turn from that point and that should be pretty close.