How to make a LSIO image from a systemd install?

Hi, I am trying to create a LSIO version of DWSpectrum / NxWitness, so that it would use PUID/GUID such that paths on my Unraid will have correct permissions.

The deb installer uses systemd, and I’d like some help on how to have the LSIO base image set TZ, PUID, GUID, etc., and still launch the installed services.

My so far unsuccessful version here:
Here is a “hacked working” version here, still trying to figure it out:

Any advice on what the recommended method is on converting a systemd type install to a LSIO image?