Dedicated circuit

I read a lot of posts on the subject, but my question is I have 6ga feeding a subpanel . My 220 compressor and other circuits are fed from the subpanel.
Should I run my dedicated circuit off the main or would it be ok to pull from the subpanel?
If I run from main it will be close to 100ft of wire, so would be best to use 6ga.
Or, off the subpanel which would be about 40ft, then I would use 10ga from subpanel to dedicated outlet.
Any opinions?
Hey skids, ask these geniuses what their advice is based on. I’ve installed panels, sub panels, wired my house, wired my listening room three times, first with a conventional circuit, then direct 4 ga, then had that cryo’d, then converted it to 220V with a step down transformer, then treated the whole length from panel to conditioner, which I’ve modified. So if you ask me something and get an answer from me I actually know exactly what I’m talking about- including how valuable it is in terms of cost vs sound quality.

Reason I say this is the first advice is completely erroneous, and the second while technically not bad isn’t really any help either. Its just there’s a long history of providing incredibly detailed informative advice that gets swamped out and ignored in the crapstorm of irrelevance like what you already started. So you want help, ask me. Otherwise, I am outta here.
If I were to get an answer from @jea48 ,
I would take it as gospel.
Just do a search of his responses over the years and you can see why he is trusted-almost as much as the late Almarg.
Thanks for the kind words.

I concur with jea48.
+1 for Jim also..

Unfortunately, the ac compressor is going to infect the whole house, it won't be confined to the subpanel. Running a 100 foot branch circuit makes it a magnet for EMI generated throughout the house, so I would use 3-wire romex. The wire is pre-twisted and helps with rejecting common mode noise, which could be a problem at that distance.