I just had my head stuck under mine to change the oil filter, happened to catch a glimpse of the prop shaft under there & wondered how I would ever be able to get in there well enough to adjust that. Access under that v-drive sucks.
This process is best done in the water. You can be on the trailer or lift but the prop needs to be submerged.
The prop shaft has two large nuts around it that lock against each other. The way you adjust it is to hold the one closest to the prop, and loosen the other. Then tighten the one closest to the prop, maybe 1/16th or 1/8th of a turn, then lock the other nut back down.
Start the boat & put it in gear. Check out how much flow is coming thru the prop packing. Like you said, it's supposed to be like a couple drips every 10 seconds. You may have to go thru this process a few times before you get the flow right. And remember that too much is fine, but too little will burn the bushing up.
Heres a good thread to read on the subject. Good luck.