If there's no HDMI display out for intel HD620 & macOS reboots while switching HDMI; then check out the patch enabled in the config.plist posted by @krosseyed here [SOLVED] HDMI out on HD620 not working.
Thank you @RehabMan & @krosseyed.
@the-braveknight Your script makes installation a breeze, in-fact it was useful for installation over other systems as well (of-course modifying for SSDT etc.). Kudos for implementing latest best practices (ALC, VirtualSMC etc.) with due credits for the respective developers.
But there's an...
Found something interesting here - https://aprilmacdonald.com/getting-amd-switchable-graphics-working-on-hackintosh-os-x/ She says she got her 7730m to work just by loading the VBIOS. Did anyone here try to load their VBIOS to check ?