Help with Installer on Lenovo X1-C3 (Mojave)

My laptop: X1 Carbon 3rd Gen i5-5200U (HD5500) 1440p screen

My config: I followed this guide first: https://www.tonymacx86.com/threads/guide-lenovo-thinkpad-x1-carbon-gen-3-2015-model-using-clover-uefi.251383/ Upon finding it's a bit outdated I switched to this guide, because the former guide was based on a previous version of it: https://www.tonymacx86.com/threads/guide-lenovo-thinkpad-t440s-using-clover-uefi-hotpatch.279492/ (files: https://github.com/Sniki/Lenovo-Thinkpad-T440S)

I looked at the DSDT patches in the post about the X1 Carbon and the T440S and they were semantically identical except for the battery one - but a comment there said it's just a carbon copy from an older version of the T440S config thus I had decided to use the hotpatch DSDT intended for the T440S. DVMT-Prealloc appears to be 32MiB can't be set in BIOS and neither can it be set from an EFI-shell thus I changed the graphics injection section to contain:

 <dict> <key>AAPL,ig-platform-id</key> <data>BgAmFg==</data> <key>framebuffer-patch-enable</key> <integer>1</integer> <key>framebuffer-stolenmem</key> <data>AAAwAQ==</data> <key>framebuffer-fbmem</key> <data>AACQAA==</data> </dict> 

I also changed the ProductName to MacBookAir7,1. Problem: It boots (the installer) fine until it switches from verbose booting to showing the apple logo with a stuck loading bar. Depending on the ig-platform-id this logo is only shown on an external monitor on the HDMI connector and the main monitor turns black. I assume all that means it gets stuck initializing graphics - but trying the different (mobile) Broadwell graphics platform-ids nothing seems to work. Does anyone have recommendations what the graphics section might be missing?