MBP5,2: running 14.3b1 with 1.3.0 fine on internal SATA SSD.
First tried to install OTA over 14.2 which failed halfway through (then system volume appeared as ...- Data, data volume as ...- Data - Data as observed earlier already).
Clean install worked well: erased SSD partition, installed 14.3b1 from "USB" installer (in fact, from another SSD partition made with createinstallmedia starting with InstallAssistant). No use of migration assistant during installation, instead using it after installation and login completed; migration from a Time Machine backup of my production MBP11,1. After migration, root patches applied. This sequence is as described in OCLP doc.
Extra remark: before applying the root patches, I forgot to set up Ethernet cable connection properly. Although the host system was set to MBP5,2 automatically, OCLP applied the KDK-less patches for MBP11,1 (somehow taken over by migration?). Didn't do harm. After correcting Ethernet, root patches properly loaded KDK and applied the proper patches.
Photos e.g. fine, and the system is quite responsive. The only slight disturbance, non-functional "show desktop", still there with 14.3b1 and 1.3.0: the frame around the desktop is drawn but windows won't go out of the way.
Great that this old MBP5,2 works so well. It is only a testing machine now but I'll use it for the rest of today.
Thanks to OCLP developers!