Mark,

    You have to be careful with that much contact. Basically with the thicker blades there is much less flex and you can put too much stress on the bearing causing premature failure. My understanding is for the 3.5mm blades to have 1-1.5" contact vs. 2.5" with the 3.0mm.

    I gleaned the following information off of one of the classrooms at the No-till conference this year. One of the moderators worked at a business setting up planters(Kinze I believe), and his 'rule-of -thumb" was to shim them(3.5mm blades) to where they will just spin opposite each other{spin one up/other down as you are looking at the front of the v} just using the palms of your hands and turning each against each other. If they do not spin, then to tight, add shims. If they spin easily, too loose, remove shims.

    Said he has done enough setups to know that this technique usually provides the 1-1.5" contact required without looking.

   I hope that was clear as mud.