I've adjusted the front adjustment screw to lengthen the drive. It's still lurching a little but it's hardly noticeable compared to what it was. This also fixed the problem I had where it was slipping out of drive. Do I need to lengthen the back nut or shorten it to see if this would help with the lurching?

 

My adjustment is on top of the gearbox, so we have different gearboxes. But I'm pretty sure they work the same inside. I would figure out where the shift lever was when it was popping into neutral, and where the shift lever is now where it runs pretty good but lurches a bit under load. Then adjust it so it goes a bit further in the same direction between 'popping into neutral' and 'running sort of OK'.