This might be the problem in your case. You have to fill the hollow shafts before you will see oil oozing out the rockers. You probably aren't seeing the oil ooz out because the shafts aren't full yet so you rotate past the alignment of the oil passage. It's a catch 22. Next time you try priming before you start try this. Remove a rocker shaft hold down bolt and fill the rocker shaft with an oil can or equivalent through the bolt hole. Repeat for other side. Replace the bolt and repeat the priming process as you have been doing it. Don't forget to re-torque the hold down bolts. Hope this works for you.