12mmT4 vs. 11 or 13mmT6

Does anyone have, or have used, both of these Nagler EPs in a fast Newt without a paracorr? I would be interested in your observed pros or cons of the 12mmT4 compared to either the 11 or 13mmT6. Which do you generally consider superior and why for the types of observing you do?
Thx.

I switched from a 13T6 to a 12T4 mainly for comfort and eye relief. They both work great in my f4.7 dob with no edge problems in either. It's a little tricky positioning your eye at first, but I quickly adjusted to it. Also, I was always cleaning eyelash oil off of the T6, I've never cleaned the T4 in the two years I've had it. YMMV

Hi William,
My $.02.
The 13mm T-6 is a good EP with most all the attributes of the Nagler line. The short eye relief is it's worst trait and those with glasses will find it to be difficult to use without taking the glasses off.
The 12mm T-4 has more eye relief and the Insta-Adjust allows one to adjust for the eye relief to suit their vision.
They both give similar views, though to me the 12mm T-4 is somewhat more immersing or porthole like in effect. The on-axis and off-axis performance is similar in both EPs.
The 13mm is smaller so that can be a factor in your preference. The 12mm has 1.25-2" ability which can also be a useful attribute.
I have the 12mm T-4 and I did own the 13mm T-6 so I have used both. I am now evaluating the 5-7-9mm T-6 EPs and they are just like the 13mm in most every way. Nice DSO EPs with a wide FOV and sharp on-axis performance. Great for Planetary Nebula, small Globular Clusters and other objects that require power for good resolution.
Which is superior? Well, not sure one is superior, just different in their feel and design.

Hi William
I've never used the 12T4 or 11T6. However, I've used the 13T6 for about 4 years in a previous TV85, TV101 and currently NP101 and SM11" f/5.4 and I couldn't be happier. I do not ware glasses to view and I haven't been bothered in the least with eye relief. My 13T6 always comes out of the box if I get a scope out.
Just my $.02
Buck

William,
I had all three eyepieces at the same time and spent many a night using them trying to decide on which I liked better. The T6 11 and 13 are superior eyepieces as far as contrast and edge sharpness goes, but I sold them and kept the 12T4 because it gave a bigger "Wow" factor in the view, probably due to the longer eye relief. This was in a 16" f/5 scope. The 12mm T4 is my favorite eyepiece in the box and gets used every night out!
David Paessler