Hi Chris, again apologies for having missed your posts. I've realized that I'm having problems getting forum notifications so I need to check in much more often.
I must admit to knowing absolutely nothing about Macs, having never so much as touched one in my life (a deliberate choice). I really have no idea what would be involved in compiling for Mac, but maybe for someone comfortable with that OS and a bit of programming experience it might be less difficult than I imagine. It awaits someone to try, but be careful also, because once you create something you then have to maintain, update, and support it for life, which we don't always think about at the beginning!
Oh and I would be happy to recommend changes on a pull request from the fork if helpful.
With regards to the Windows version, yes do feel free to recommend changes using pull requests, though we can also discuss here in advance. The main update to OP Config that would be nice is exactly what you've identified, the issue with High DPI screens. That appears to be an easy fix as you've discovered, but fixing all the things that the fix breaks may prove more tedious. However again I would welcome with gratitude any improvements others want to devote themselve to, and will try to help as I can.
One of the main differences in the later version is the settings in the user file but of course that contains user specific environment variables/paths and aren’t great for inclusion in the source control as it isn’t transferable between different environments. Might have a think about that too.
I may not know what this file is if it's specific to later versions of Qt, but even in my version there is an OpenPanzerConfig.pro.user file which I believe is the equivalent of what you're talking about, and yes, it's not of much use to share it. I think it could probably be left out and theoretically the environment would create it for whoever is compiling the source.
I would love to build a board specifically or the Heclo hat but I’m starting with a few separate components at the moment just to get my head round it a bit.
That is definitely the right approach to take! The result of your experiments with individual sections will go a long way to informing what kind of board you will ultimately want. Starting with a grand unified design at the beginning will always result in a lot of revision later on, or anyway that's my experience.