Hi Gordon,
Easily the best advice is to try before you buy, if possible, as eyepieces are very subjective. To some people their goal is to maximise field of view and edge performance, others seek long eye relief, sharpness and high contrast. Others prefer a mix and match of all of these things.
I own or have used just about all the best eyepieces available at present, including all the Naglers. Ethoi, Pentax XW's and the Denkmeiers. I also own a 10"/F5 dob, a 14"/F4.5 dob and an 18"/F4.5 dob as well as regularly using 20", 25" and 30" Obsessions and SDM's.
Knowing what I know and liking what I like, this is what I would be doing.
1. 10mm Pentax XW. Simply one of the very very best eyepieces money can buy at any price for use in any telescope. It also barlows very well in the 2x TV barlow for a 5mm eyepiece.
2. 14mm Denkmeier. If you are happy to accept a 65 deg AFOV this is optically the best eyepiece available at this focal length. It has no faults and excels in every eyepiece performance criteria. That comment is coming from someone who owns a 12mm Nagler T4, a 13mm ETHOS and a 14mm Pentax XW. As an added bonus it has 20mm of eye relief. In addition, it is a 1.25" eyepiece and barlows very well in the 2x TV barlow for a 7mm eyepiece which will be a very handy focal length in your 10"/F4.7 scope.
Here is a comparison with the 14mm Denkmeier.
http://www.cloudynights.com/item.php?item_id=2087
Nick Koiza who wrote this review actually purchased the 14mm Denkmeier on my recommendation a couple of years ago. I agree with about 98.5% of his review. It is a very accurate assesment.
3. 26mm Nagler T5. IMO this is a better eyepiece for use in smaller scopes than the 31mm Nagler T5. However, be aware it may cause balance issues in a 10" scope and you may need to adjust the tension control (if you have one) or use a counterweight. Note that it is smaller and lighter than the 28mm UWAN.
Some comments in regard to your original choices.
1. You may have read some good things about the 28mm UWAN. I have used one and do not like it. I know several other observers who feel the same way. I couldn't put it in the class of the 26mm or 31mm Naglers, or the 30mm Pentax XW, which in itself would be an excellent option.
2. The 17mm Nagler T4 ( I own one) is a very heavy eyepiece and could cause balance issues in your scope. On top of that it is a 2" eyepiece and you cannot barlow it in your 1.25" barlow, which means you are losing some versatility. Most importantly however IMO it is one eyepiece which really benefits from using a paracorr, particularly in scopes faster than F6. In your 10"/F4.7 scope the 14mm Denkmeier will, outside of FOV, be a clearly superior performer. Further, in a 10"/F4.7 scope I consider 14mm to be a far more useable focal length than 17mm.
Cheers,
John B