I would echo dangle's comments. I consider myself a complete gearing dork and have created many a spreadsheet like yours (nice job, by the way)! I have a pile of cassettes and will often change up to get the optimal gearing for the day's ride. Just figure out the highest and lowest gearing need, then try to fill in the cogs to make the tightest block at the lower end of the tooth count on up. I run Shimano Ultegra 11 speed on my road bikes and have had excellent success mixing cogs from different out-of-the-box cassettes to come up with the best combo. As long as you don't use a crazy leap in teeth on adjacent cogs, they shift perfectly. That's just my experience, anyway.

I have no experience with SRAM Red, Rotor or Edco cassettes, but I would be reluctant to go that route simply because I am nitpicky about drivetrain noise and would have the concern that mixing chain and cogs from different manufacturers would not be satisfactory from that standpoint, let alone perfect shifting. For the $250 price of some of those, you could probably pick up 3-4 Ultegra cassettes and have all the gearing options you'd ever need.

Unsolicited opinion, but FWIW, I'm skeptical of 1x applications on the road, particularly in the realm of TT bikes. Specifically, I'm skeptical any aero benefit outweighs the added drivetrain friction from chain deflection (which I would think is greater on a bike with shorter chainstays) and the potentially suboptimal gaps between gears. In TT mode, at least for me, the right cadence is paramount. Being stuck between a gear that's slightly too large or slightly too small is something I'm keen to avoid, even if it means I'm losing a few seconds worth of aero drag.