There has been a lot of discussion about proper oiling for Holset and Garret turbos (see these two threads):
Holset HX-35 Oiling
Garrett & Holset Turbo Users - Your Oil Drain May Be Too Small!
Both of these threads have pointed out the importance of proper oil flow at the turbo itself. Too much oil without proper draining will blow turbo seals. Too little oil will starve the turbo at high RPM. The above threads discuss the pros/cons of feeding oil from the head or oil filter housing (OFH) as well as selecting a proper oil return line. To be sure you have made the right selections, the best way I can think of to check for proper oil flow is by hooking up an oil pressure gauge inline with the oil feed as close to the turbo as possible.
After reading up on the topic of proper oiling for Holsets, I chose to feed the oil from the OFH with a restrictor, and I bought a -10AN oil return line from MAPerformance. (I should note that I have removed the balance shafts.)
I used one of these eBay inline -4an .075 oil restrictors
Here's a picture of the restrictor inline with the oil feed from the OFH. I put the restrictor as close to the OFH as I could because some people have said that it is bad to run a restrictor right at the turbo because of the spray effect they tend to have.
Next I bought a cheap -4an swivel fitting
from Summit Racing that has a 1/8npt female opening so you can tap in an oil gauge. I put this right before the turbo just to be 100% sure I was seeing oil pressure at the turbo. This adapter was a temporary installation, just to see oil pressure at idle, free rev, and driving before taking it off.
I temporarily mounted the gauge to the windshield by holding it in place with the windshield wiper. :) I was showing around 15psi at idle (sometimes just below 10psi on a rough or low idle), and right around 65psi at WOT throughout the RPM range. Once I was satisfied I removed the adapter and hooked the -4an feed directly to the turbo:
At the time of writing this I have been running this setup for a year with no issues. The turbo is still strong and it hasn't smoked one bit. Remember that every car is different and you should test your setup before running it. To see the full install, check out the article on my blog!