NO "tee" needed.
Simply re-route the line from the BOTTOM of the oil filter cannister to "dump" into the governor INSTEAD of into the block, as it does now, and plug the unused hole in the block.
DO NOT mess with the plumbing on the side of the filter that is in common with the oil pressure gauge.
(The oil flows FROM the fitting the filter and gauge share INTO the outer part of the filter cannister, inward through the filter, then into the "rod" in the center of the filter and OUT the fitting at the bottom of the filter to return to the crankcase (or the governor). I'm GUESSING you think the oil flow is the other way.)
The filter is a "by-pass filter", fed through a restrictor oriface, so only 10 to 20% of the system oil goes through the filter, then "wastes" back through the fitting in the side of the block and simply runs down into the crankcase, NOT into the engine bearings, as you may be suspecting.
It is NOT a "full flow" filter, where ALL the oil goes through the filter, and then on to the oil gallery, and ultimately on to the bearings, as in "modern" engines.
You are NOT "teeing" into anything, or changing anything that will reduce oil pressure. You are simply taking the flow of oil that now simply flows back into the oil pan, and re-routing it so it lubes the governor on it's way back to the oil pan.
I HOPE this explains it better????