Then I think also the old design is far away from you needs. The original name of the C4-SFX was C4-H2O. So this case is design around using a 240mm AIO. The most powerful air cooled heatsinks that you can install is a AXP-100 or BigShuriken these cooling solutions has no chance against an 240mm AIO.
Dan, thanks for your personal reply; very nice to hear from you.
I have been advised (maybe incorrectly), that AIO coolers are not ideal long term for rigs that are regularly moved and transported.
Possibly someone can refute that and add their experience. I can see the benefit of a 240 AIO taming a hot running higher TDP CPU in a small case, so am not against it generally.
Nevertheless, I will still watch the C4 development process with interest, as I have been with it for over a year already.
I'm pleased that you have got your 2nd product, the CPU cooler off the ground; having a second case in the product line would really strengthen your position in the high quality SFF market.
In the meantime, I will work on my NCase M1 build and see how it works out for my needs.
Best wishes to you and your family