So basically what I’m understanding is this:
You’ve been running Emperor, Emperor: House of Medici, and Stark in a stack for the past 6 months. And prior to that you were running Emperor and Emperor: House of Medici for around 2 years. (That sounds awesome, by the way).
On top of that, you have already been experiencing great synergy and compounded results from Emperor, HoM, and Stark. In other words, the combination is already working very well for you.
If this is true, then you’ve already addressed pretty much the main controversial point of your proposed custom: the number of major program cores.
You have a reasonable experiential basis to imagine that these cores will combine effectively for you. Your mind has already been creating the archetypal structure that can effectively integrate the three programs.
Looks like a reasonable build to me.
The Ascension Chamber issue is, i believe, not so extreme. Ascension Chamber is a highly-focused, if powerful, program. It’s not doing 300 different things, and it is meant to integrate with other programs. Moreover, while the standard version of Ascension Chamber is Terminus2, it will be adjusted to the build strength of your custom.
Just keep in mind that you’re building a dense custom. (I have a lot of experience with that; and the main thing I’ve learned is that I need to give my mind more time to integrate them. Your own experience may vary.)
If you build this program, it would probably be a good idea to play it alone for a while. When you build up confidence that your mind is processing it and integrating it smoothly and well, then you might make additional moves.