When one is trying to learn this stuff on his own there is no place to easily find basic information like what viscosity is recommended. I guess that in the many YouTubes, etc, it is assumed to already be known by the watcher/reader. But I am trying to learn the tools that real installers who know how to make an install last use; micron gauges, nitrogen, torque wrenches. I believe I am close 99% there, but that last 1% has been very hard.
For example - the importance of torque wrenches. A lot of even "professional" installers don't use them in videos I have seen, but I have now seen 5 minis and they were all seriously under torqued (I know now since I bought my CPS). If I didn't have a micron gauge I would always assume almost any pump worked because they can all draw to ~-30 sea level on a manifold and hold for 30 minutes, but with the micron gauge I know that is meaningless. Because I bothered to get a cylinder of nitrogen I was able to find small leaks and redo some flares that are now tight as a drum (for positive pressure).
See - many would call me a DIY, but DIY clips are no use to me, (no nitrogen, no micron gauge, no torque wrenches) if I wanted to claim that route I could say I am already 100% ready to go.
For DIYs, there is no warning that vacuum pumps are so complicated. I didn't even realize most of them are for car maintenance, (I am not a car mechanic), I assumed they were for HVAC. It took me a week to figure out what I needed to get for a 3/8" end for my Appion vacuum-rated 3/4" hose to fit on a pump. Most pumps are made for car coolant hoses. No one would or could tell me the problem. One experienced but noted YouTuber told me to take my hose and pump to a hardware store and make sure they got it to fit.
I am just a guy who likes to fix things. I just rebuilt my neighbor's LED TV last night from the bottom panel up and it works perfectly now (he had 9 dead LED strips). I learn well on my own but I also rely on what's on the web. But there is a lot in this field where the info is not out there in public. I'm not complaining - just explaining.
Your answer is helpful, I appreciate that. Not sure I get your question on the price of vac pumps unless you are trying to tell me to use 46. Even most pump manufacturers do not tell you what viscosity to use unless you figure out it is an ISO standard. The bottles they send out with the pumps do not even say anything.
Anyway - up above I explained that I had just tried the "break-in" process and changed the oil not long before the new pump crashed on me. Maybe I made a mistake (probably) but so did a lot of other people who bought the same pump and had the same complaint.
I just looked at the Harbor Freight pumps and their fittings don't work with my Appion vacuum-rated hose, so I am looking for a different pump. I prefer to buy from Amazon because I am prime and get free fast shipping and guaranteed returns. Not sure if they have what I need in a pump, though. They have CPS but through a third party so the shipping is slow.