Windows Targeted RHIs - How To Make A Game For Low End PCs

I was looking into how to improve the FPS for low end PCs and came across this great post on how to use the Open GL ES3.1 mobile renderer on windows to get better FPS: https://www.unrealengine.com/blog/how-disc-jam-reached-60-fps-on-intel-processor-graphics-using-unreal-engine-4

My first question: Is it possible for EPIC to add the PCD3D_ES31 RHI into the windows targeted RHIs list for the standard unreal build so we can use the same technique as in the above article without having to manually change and recompile the editor source code ourselves?

Second question: Does anyone know what command line arguments to use to get any of the below RHIs that are already in the Windows Targeted RHIs list on 4.14 to run on Windows? (the same thing as the MyProject.exe -featureleveles31 that the above article uses)

Currently in the 4.14 Editor -> Edit -> Project Settings -> Platforms -> Windows -> Targetted RHIs, I can see:



**Name in Editor              RHI Text           Command line argument used to run (I.E. in the above article they run MyProject.exe -featureleveles31 to run the RHI PCD3D_ES31)**
DirectX 11 (SM5)            PCD3D_SM5          Packaged projects use this by default for me
DirectX 10 (SM4)            PCD3D_SM4          Use the command line argument -d3d10
OpenGL 3 (SM4)              GLSL_150           ?
OpenGL 4 (SM5, Exp)         GLSL_430           ?
Vulkan Mobile (ES3.1, Exp)  SF_VULKAN_ES31     I would be especially interested to know the command line argument to run this RHI
UnknownRHI                  GLSL_150_ES2       ?
UnknownRHI                  GLSL_150_ES31      I would be especially interested to know the command line argument to run this RHI
Wolf (Forward)              GLSL_WOLF          ?
Wolf (Deferred)             GLSL_WOLF_FORWARD  ?
Vulkan Desktop (SM4, Exp)   SF_VULKAN_SM4      ?


Thanks in advance for any help or thoughts anyone has!
.

based ob my personal experimentation this is what worked for me

DirectX 10 (SM4)
-d3d10
-dx10
-sm4

DirectX 11 (SM5)
-d3d11
-dx11
-sm5

OpenGL 4 (SM5, Exp)
-opengl4

OpenGL 3 (SM4)
-opengl3
-opengl

OpenGL 3 (ES3.1, Exp)
-opengl -FeatureLevelES31

OpenGL 3 (ES2)
-opengl -FeatureLevelES2

Vulkan Desktop (SM5, Exp)
-vulkan -sm5

Vulkan Desktop (SM4, Exp)
-vulkan -sm4

Vulkan Mobile (ES3.1, Exp)
-vulkan -FeatureLevelES31
-vulkan -FeatureLevelES2