Got an earlier version of the board after seeing your video (made in USA - visibles almost identical) - nice sturdy module. Here are my observations and thoughts, having spent the night with it.
With a 4.7k trimpot on the (lm342 OUT2) -> (HIP6004 VSEN) in place of R11 (normally 3.4k), we can convince the HIP6004 to alter output within new range i.e. 4.1k=3v, 2.3k=4v, 1.1k=5v etc. Great with no load. But there is a pesky feedback loop (I think) HIP6004->LGATE switching the Overprotection FET on creating a dead short to ground (therefore blow input fuse to protect the output). That feedback loop is fed by the HIP6004 monitoring the voltage drop across the Upper/Top FET (the TO220 FDP7030).
When reviewing my initial thoughts were to pop the HIP6004 and put another micro PWM controller on there, but in retrospect less is so much more. Mulling removal of the D-PAK (HIP6004 OVP) overprotection fet, simply seems most practical for my potential use case as a low current stable supply. There is a fair few passives on there obfuscating matters; but fundamentally cant foresee too much of a problem there.
After Lifting the gate of the overprotection fet (HIP OVP) - it all works like a charm (limited testing few hundred milliamp).
P.S. The through hole barrels securing the heatsink posts are solid - iron at ~ 330c, bit of fresh lead; screwdriver pry-bar; the heatsink came off a treat!