Strange told me I didn't need them either. I run standard US Gear 4.10. 90 passes so far. Foot brake 1.32, 9.25,147 @3340 lbs. I was told standard gears would be fine. I can tell you I experimented with the pattern when setting them up. By adding .010" additional pinion cup shim the pattern covered an area nearly twice as wide on the face of the tooth. I thought it looked pretty decent to start with but it kept getting a wider contact patch as I went. I also made sure I had proper pinion and side bearing pre-load.
Doug