My overall thinking in terms of Trek history and technology also doesn't follow the "official" version.
In 2018 Earth develops the impulse drive or some form thereof which allows for fast relativistic starflight and to break free of the solar system. This allows velocities in excess of .9c
. Around the 2060s Cochrane develops his space warp superimpellor. It's a bit vague on whether he developed simply the mathematics and formula or an actual working drive system, but more than 150 years later he does recognize Spock as a Vulcan so evidently Cochrane's development results in actual warp driven starcraft within his lifetime (I don't buy FC's assertion that Vulcans basically rescued us and helped raise us out from being a bombed out civilization).
From Cochrane's development onward the space warp formula is basically the familiar one cited in The Making Of Star Trek:
speed = WF cubed x the speed of light. And this formula stands until about the mid 2240s when Richard Daystrom's duotronic systems revolutionize computer technology particularly in terms of propulsion, navigation and guidance as well as the development of viable teleportation systems. Daystrom's systems are now sufficiently fast enough for the computational and processing speeds required for such real advancements. It's the leap forward, the genuine dividing line between the "primitive" technology cited by Spock in "Balance Of Terror" and the current TOS era. It also gels with Jose Tyler's reference in "The Cage:" "You won't believe how fast you can get back (to Earth). Our new ships can..." There is a subtext throughout TOS that not too long prior to the Pike era interstellar starlight was rather more rudimentary than what we see in the TOS era. My idea is that in the "modern" era the warp flight formula is WF cubed x .02 = light years per hour. This redefining of the warp formula now really allows for the velocities and transit times referenced in throughout TOS.
There is another subtext throughout TOS that the Federation also isn't that old---perhaps only decades and not a century as cited in TNG and the rest.
This is how the design currently stands.
I'm thinking of building two variants of my 22nd century clipper: the exploratory ship seen above and the transport variant. I actually envisioned the Woden
seen in "The Ultimate Computer" as being one of these old transports converted to automation.
The detail work is going a bit slowly as I think it through. I want to add detail that enhances the design with interesting visual texture and yet I don't want to overdo it because I want the ship to look like it could belong in the TOS universe.