Look at the Acidanthera WhateverGreen FAQ UHD 630 CML for a list of device-ids. Using alternates is common approach. See the "Spoilers" link, it's easy to miss.
Also look at the WEG README for options that pertain to HDMI and clockrate.
The OpenCore Install Guide presumes fbmem / stolenmem config for all Comet Lake, but also does not consider it boilerplate, so its not unreadable to include it — If anyone can help by referring to a more comprehensive writeup, please report!
Meta-commentary:
WEG seems has grown more self-configuring over the years, so advice to begin with no config or minimal config is correct.
But this of no help to know except as baseline for entire hack approach! "Don't config what you don't need." But how do you know if you need it?!
If you carefully read the docs, WEG features clearly pertain to specific hack situations in history which aren't discussed in the docs. Many patch options are listed, but rarely include any specifics of when, why, how any patch is needed. It's a chicken/egg of you are supposed to know when you need a fix, but all you have to go on is a symptom which can be caused for many reasons. — Notice how many patches pertain "black screen problem" without any other details, when there are patches such as adgpmod=pikera which are expected to cause black screen (on iGPU) when used properly.
These forums are filled with great work, but are nonetheless pathetic at curating understanding of solutions... The same situations come up over again with no catalog of find previous experience — anyone who says "just search" is not paying attention to what's actually going on with knowledge on these forums.
Moderators are not so moderating but squelching and working like personal gurus answering the same questions over and over.
In some cases such as USB config and framebuffer patching there are good efforts made to organize knowledge, but it's still a mess of lore over edge-cases, and the exposition always has huge gaps in language or ambiguous tools.
For example, when you are looking at any Hackintool output, how do you know when it's reporting your specific kit versus your specific config for your kit, versus
it's idea of specific config for your kit? If you already know, you don't care about the answer and move on, but if you don't know you can't figure it out from the tool. This leads to thread-after-thread of explanations that don't explain, just report "do this because it's known to work sometimes". WHICH EXPLAINS WHY PEOPLE ARE PUTTING FBMEM / STOLENMEM IN THEIR CONFIG!
Meanwhile the guys writing WEG may be coding workarounds to deal with what is now common case of idiots always putting unifiedmem options on their config.
Seriously, if you track down agdpmod=pikera lore, which is a most common way to get AMD dGPU output, you will find 4 years ago R.A. Pike discovered overriding board-id with board-ix or "whatever you want" is secret sauce to a change in Apple Graphics Device Policy, then his son's wife died which he describes in the 3rd person and he quit the web forever:
Dateline 2018:
A long time ago (read seventeen months ago) I blogged about the changes in the AGDP (Apple Graphics Device Policy) and had to came up with a workaround for an issue in AppleGraphicsDevicePolicy.kex…
pikeralpha.wordpress.com
//A long time ago (read
seventeen months ago) I blogged about the changes in the AGDP (Apple Graphics Device Policy) and had to came up with a workaround for an issue in AppleGraphicsDevicePolicy.kext so that we could use a MacPro6,1 board-id/model combination, without the usual hang with a black screen.//
I AM NOT MAKING THIS UP! This is the root of an entire zone of knowledge about dGPU config according to the most comprehensive write-up so far, Dortania, (which btw is not related to Frito-Lay or Pepsi).
While it would be great to see a writeup on when / how to use the fbmem config that explains what's going on internally, there already is detailed documentation at github for WEG which treats is all as pure effects. — I've never tried to read the source code, maybe that's the best way to know.
So as to people who post "my kit doesn't work" threads and moderators who have to point out for the thousandth time "Your config.plist a total mess", it's because that's how knowledge works here. We actually don't want to know, because it would spoil the fun!
— BTW If hacks were costed for time, they could commonly hit $20,000! Which either makes Apple's prices seem way more reasonable or points to a dread flaw in our society's comprehension of value.