I've found an ig-platform that works perfectly for my 20KH (04002759). The screen sleep problems are gone! The screen also properly restores after sleep (no weird resolution issues).
<dict>
<key>AddProperties</key>
<array>
<dict>
<key>Device</key>
<string>IntelGFX</string>
<key>Disabled</key>
<false/>
<key>Key</key>
<string>AAPL,GfxYTile</string>
<key>Value</key>
<data>AQAAAA==</data>
</dict>
</array>
<key>Audio</key>
<dict>
<key>Inject</key>
<string>No</string>
<key>ResetHDA</key>
<true/>
</dict>
<key>Properties</key>
<dict>
<key>PciRoot(0)/Pci(0x02,0)</key>
<dict>
<key>AAPL,ig-platform-id</key>
<data>BAAnWQ==</data>
<key>AAPL,slot-name</key>
<string>Internal</string>
<key>device-id</key>
<data>FlkAAA==</data>
<key>device_type</key>
<string>VGA compatible controller</string>
<key>enable-hdmi20</key>
<data>AQAAAA==</data>
<key>framebuffer-con0-enable</key>
<data>AQAAAA==</data>
<key>framebuffer-con0-pipe</key>
<data>EgAAAA==</data>
<key>framebuffer-con0-type</key>
<data>AAQAAA==</data>
<key>framebuffer-con1-enable</key>
<data>AQAAAA==</data>
<key>framebuffer-con1-flags</key>
<data>hwEAAA==</data>
<key>framebuffer-con1-pipe</key>
<data>EgAAAA==</data>
<key>framebuffer-con1-type</key>
<data>AAgAAA==</data>
<key>framebuffer-con2-enable</key>
<data>AQAAAA==</data>
<key>framebuffer-con2-flags</key>
<data>hwEAAA==</data>
<key>framebuffer-con2-pipe</key>
<data>EgAAAA==</data>
<key>framebuffer-con2-type</key>
<data>AAgAAA==</data>
<key>framebuffer-con3-enable</key>
<data>AQAAAA==</data>
<key>framebuffer-con3-flags</key>
<data>hwEAAA==</data>
<key>framebuffer-con3-pipe</key>
<data>EgAAAA==</data>
<key>framebuffer-con3-type</key>
<data>AAgAAA==</data>
<key>framebuffer-fbmem</key>
<data>AACQAA==</data>
<key>framebuffer-patch-enable</key>
<integer>1</integer>
<key>framebuffer-stolenmem</key>
<data>AAAwAQ==</data>
<key>hda-gfx</key>
<string>onboard-1</string>
</dict>
<key>PciRoot(0)/Pci(0x1f,3)</key>
<dict>
<key>#PinConfigurations</key>
<data></data>
<key>hda-gfx</key>
<string>onboard-1</string>
<key>layout-id</key>
<integer>11</integer>
<key>no-controller-patch</key>
<integer>1</integer>
</dict>
</dict>
<key>USB</key>
<dict>
<key>AddClockID</key>
<true/>
<key>FixOwnership</key>
<true/>
<key>Inject</key>
<true/>
</dict>
<key>UseIntelHDMI</key>
<false/>
</dict>
</plist>