I have been pushing the game to see where my system's limit is. I thought I had found that limit with ~200 mods (~150 plugins), many of them heavily scripted and several HD texture replacers (always using vanilla ugrid and papyrus settings). After recently installing several more script-heavy mods, I started getting CTD's on load, repeatedly (no missing masters). I had found my limit.
Not sure how I've missed it for so long, but since finding info on the memory problem with 'Stable uGridsToLoad' and removing the mod, my CTD's have stopped.
Without any doubt 'Stable uGridsToLoad' was the culprit. My guess is that with the heavily-modded state of my game, the effects of it's memory corruption problem was amplified.