In the case of my Big Gonzo build, I wanted to build a 6538 Big Crown Sub that would hearken back to the days it was for sale in the showroom. What does that mean?
Back then it was a nice durable watch that could go in the water, nothing more. It had no aura of "Bond" or exclusivity, it was a tool. I'd think it would be a lot like a good Seiko diver today, not very expensive and pretty durable. I'd never think twice about taking a Seiko in the ocean, and if I dropped it on the desk at the end of the day I wouldn't notice or care. Nobody in their right mind would do that with a genuine 6538 today.
So I used a sturdy aftermarket case and bezel with the right dimensions, got lucky with a gen crystal and found a gen crown and insert for good prices. I finally found the dial I wanted, and into this housing I plunked an ETA movement. Heresy? Nope. Just like a 1030 movement during the 50s and 60s, the contemporary ETA is robust and easy to find parts for. If I flood it and ruin the ETA, it will be no big deal to simply replace it. Not so with a 1030.
In the end I have a watch that's impossible to tell from gen without a strong loupe, or by opening the back. I get to use it any way I want, with total disregard for it being "Bond" or exclusive. In a way it's taken me right back to the 50s and 60s, and I get to use it swimming and diving ... like it was meant to be. That usage is what I've replicated.
There's a lot of freedom and enjoyment in that. You can replicate the usage of a tool stopwatch with your 6263 the same way.