A friend of mine, Watt Bigem that is an engine builder and has a nice machine shop in Lavon Teaxs named Watt's Shop is a Master WD for the Brad Penn Oils. I know he stocks a good diverse supply and will give you fair pricing.
I do not know his pricing but his phone number is
972-853-2647
If you need to email instead the email addy is
[email protected]
Ed