Hi Mel
I have the Nav 17/14 and is excellent looks like you could reach in and grab the stars, I did replace the rubber eyeguard with one off a 13 Ethos and it made a noticeable difference , Didn't go for the 12.5 as with the Nav at 14 a little too close so went for the Docter 12.5 for Ortho performance at 88 deg fov and is the sharpest with the most contrast eyepiece i have viewed through plus it comes to focus in any scope i have had it in.
The info to buy from Japan is spot on and could save you around $200 ish but you will not regret the purchase, Why not try the classifieds first it's where i got my second one bought my first one new from Japan and still can't understand why i sold it...
