Conclusion: Natasha's Performance
On 12 September 2005 we had a night of exceptionally good seeing, and for the first time I was able to see a clear optical difference between Frankenscope (good Meade mirror with good aftermarket secondary) and Natasha (premium grade primary with secondary to match). I saw an image of Mars at 400X through Natasha that was astonishingly bright and clear-- like looking at a web cam stacked digital image. It was still very sharp at 600X -- the highest I could go without digging out a Barlow. Frankenscope, meanwhile, was still stuck at the mid-300X power level, and its' image wasn't as bright nor did the focus "snap" into place the way that Natasha's did, even though both scopes were well collimated.
The following night had "good" but not fantastic seeing, but nonetheless I was able to work at 500X with Natasha. While I didn't have Frankenscope up and running that time, based on innumerable observing sessions with it I am relatively confident the seeing conditions would have capped it again at the low 300X magnification level.
Finally, empirical evidence "at the eyepiece" that made all the expense and time of 'going upscale' on Natasha worthwhile!
19 Nov. '05 UPDATE: In my contemplation of purchasing an even larger scope --ideally a 24"-- for use under dark mountain skies, I had the chance to evaluate a Starmaster 24" f/4.3 equipped with a Zambuto mirror. (For many this particular combination is the "gold standard" of amateur astronomy-- there are only 14 such scopes in existence...) I brought Natasha along, even though the Starmaster's owner pooh-poohed the idea and said doing the comparison would leave me hating my scope. After looking through it once we'd used the Starmaster for a couple of hours, however, he was impressed and likened the views and ease of use to his Starmaster 14.5", which he said was his favorite one (he'd owned every model from the 11" to the 24"). He opined that the 14.5" was Zambuto's best mirror size, too, so my Obsidian 16" glass seems to be in good company <g>. Sounds like pretty decent validation/vindication of the Natasha project to me!