Plenty of information here
http://www.televue.com/engine/TV3b_page.asp?id=154
Note too for an eyepiece such as 5mm Radian, it has 20mm eye relief with adjustable eye cup. It is much easier to view an object at 240x with a short focal length eyepiece that has a good size eye lens and plenty of eye relief than a Plossl or Ortho with a small peep hole and short eye relief.
Note too for an undriven DOB an eyepiece with 82 deg. apparent field such as a Tele Vue Nagler is desireable to keep the object in the field longer. Note the Nagler is highly corrected and will do well in your telescope (and any other telescope you choose to use it in) but you will still see primary mirror coma which can be corrected with a Paracorr. At least with a Nagler you wont see any eyepiece introduced aberrations that show themselves with cheaper options.