It seems Omten 1288 switch has resistance of about 5-7mOhm, I will too check that with 4-wire method. Djozz also reported that resistance decreases a little bit with current, and it should be the opposite - at first look this looks like good thing, but it's not - it's a sign that metal contacts inside of switch get softer/stickier due to high temperature, so contact area increases; also high temperature helps with removal of surface impurities. But high temperature means short lifetime and questionable reliability.
Also,one important thing is that djozz tested switches with pure DC current, my intuition tells me that high current DC pulses from PWM DD drivers would be much worse due to constant current interruptions and possible arching.
Conclusion is that Omten 1288 switch, or practically any other mechanical switch of similar size is not good or reliable over 5A, yes many use it up to ~12A, but just calculated power dissipation in switch at that current (~1Watt of heat) is worrying, small plastic switch cannot dissipate that amount of power in the long term.
SubZero switch has 1~2mOhm resistance (testing in progress), and great cooling (MOSFET soldered directly to brass shell), so yes,every clicky light should benefit form that, DD driven LEDs would show higher lux/lumen readings due to larger current from battery, CC driven lights would stay in regulation for longer time, and overall light efficiency would improve.
Like most people,I would not dare to sell 12A+ light with OMTEN switch to customers, and that's the reason you don't see any 9A+ custom clicky lights for sale.
With FET switch like subZero, switch is no longer weakest point that limits power and reliability.
I installed OP refl. to C8+ without any problem. It seems fit will be fine. You only need smaller gasket, because a reflector openning hole is smaller.
Hopefully I can mod your parts for Manta Ray C8.2.
I am waiting for some parts in your shop, such as Luxeon V 90CRI, C8 Spacer, possibly fitting Momentary Tailcap-Switch and so on.
When did you think, you will get the Luxeon V 90CRI?
I will offer 6x ANNA within C8 DIY kits for now, I have limited number of them. Price of spacer is yet to be determined, I will have first batch this week.