You can add a 1/4 oz. of florescent UV dye to the oil to pinpoint the exact source, or simply spray foot powder onto the area. The foot powder works pretty darn good to indicated the oil trace. Another option is to use a smoke machine in the crankcase and watch to see where the smoke comes out.
No need for any more look for tricks. I can wipe and watch it seep out in that area between the head and block.
No pressurized oil at the front of the head.
The oil drain in each corner is just that, a drain. Most of the oil goes to the back due to engine angle on most cars.
Hard to believe the source of the leak has anything to do with the intake. First thing I would do is pull the valve cover and check head bolt torque.
