I tried using unmodified sources. I tried exporting and re-exporting. I tried splitting the wim files. I tried solid compression. There are very few things that I didn't try. It's been a few years, but I seem to remember the indexes at the start being laggy but working while the later ones either hard failed or had errors. It wasn't just limitations in the setup program either. I abandoned the typical setup for my diskpart script early on. The dism infrastructure couldn't handle the work. I'm sure engineers at MS could diagnose the reasons why it couldn't keep up and recode it to work, but to my knowledge they haven't bothered yet. Ultimately my goal of making an AIO to rule them all was a failure and needed to be cast into the fire.
maybe same scripting running the setup to choose which wim to load to install from like sources folder will be install-Win7.wim install-win8.wim install-win10.wim E:\> setup.exe /installfrom:".\wims\32bitimage.wim"
Yeah I mean there is more than one way to skin a cat. Maybe these days it wouldn't seem so ridiculous to have like a 60GB ISO, but a few years back it was just asking too much. If anyone is looking into this, I can give some tips. 32-bit and 64-bit images from the same build have a certain amount of overlap, but different builds don't. For instance you could have a win10-x86-32, win10-x86-64, and the various server versions from the same build and put them all on the same install without causing much problems. But to add different builds together doesn't increase efficiency that much more than using separate install wim files.