Thanks for the comments and likes.
On another note, would you mind posting a native resolution image from this series if you still have one? I'd be interested in seeing how you come up with that amount of downsizing you end up using.
Steve, the amount of downsizing is completely random, and actually, I could have done without any, but I don't like the field of view being so restricted when people click on the "original size" image. Essentially it is too "zoomed in". This doesn't matter for anyone who downloads the image and opens it in whatever way they want, but I like things to look as good as possible with a minimal amount of work for viewers, because the viewer shouldn't have to optimize anything. Although admittedly, this is impossible anyway, for the reason described below.
I've noticed that despite the fact that high resolution monitors are now common, images are not displayed at 1:1 pixel ratios. For example, my MacBook Pro Retina display is 2880x1800 pixels. If a large image is displayed with 1:1 pixel mapping from image to screen, it looks amazing. Sadly, that's not the way images are displayed by default. Apple lets you choose the screen resolution, but in all cases the screen is rendered to simulate a lower resolution screen. They do this because text and graphics would be tiny if web pages displayed at 1:1. This does give a realistic look at what lower resolution monitors will show. Those monitors might actually be displaying true 1:1 pixel images, but because they have larger pixels, the image is very zoomed in and looks poor. So, downsizing the image helps keep the panorama from becoming overly zoomed in when opening the "full resolution" image. So really, this is simply a problem with web display. Flickr is particularly bad, as are most of the other photo sharing sites. There aren't many good ways to showcase 10,000 pixel images on the web, but a smooth pan and zoom feature would be ideal, similar to what the LRO Quickmap offers. But ultimately, I chose the 70% scale because it retained most detail, but kept the size under control. Honestly, a 50% scale looks even better on low resolution monitors (or my MacBook's simulation of such), but then you do start to lose significant detail. So it's a bit of a game. Also worth noting is that the same image looks different depending on which program you use to view it (on the web browser, Photoshop, Preview, etc), because they all resample the image to different degrees.
The other issue here, although of lesser significance, is that when we capture images at the diffraction limits of our equipment, we are also fully sampling diffraction artifacts, as well as a host of other things that conspire to degrade the image. Notably, if you look at the image scale produced by the Narrow Angle Cameras (NACs) onboard the Lunar Reconnaissance Orbiter (LRO), you find some interesting information. Each NAC utilizes a Ritchey-Chretien telescope of focal length 700mm, aperture 198mm, f/3.5. The pixels of its digital camera are 7um. Now, if you follow the general guidelines of amateur imaging, you would image 7um pixels at f/35, which is 10x higher than what the LRO is doing. Imaging at f/3.5 gives them very clean images. The resolution of those images comes from the extreme proximity to the Moon, not from the power of the telescope used. Unfortunately, there are no real lessons we can apply here as amateurs, because we have no choice but to image at longer focal lengths. But it is true that downsampling images can make them cleaner, at the expense of resolution. I've mentioned this before in the context of LRO images, in which downsampled WAC mosaics that produce similar image scales to modest amateur images have far more detail than those images.
All of that said, my decision was arbitrary and not based upon any specific measurements. Below are 100% reproductions of a section of each image. They look amazing at a true 100% rendering on my monitor, but slightly too large at the "fake 100%" scale that is typically shown on the web. The extra pixels aren't very helpful for web display, but would come in handy for making large prints at 300dpi.