Hello Adam. I'll link you my experience with the GSO/Bintel 2" ED Barlow.
http://www.iceinspace.com.au/forum/s...d.php?t=107743
Just for clarification, because its not mentioned in my thread, for my canon DSLR I use the t-adapter directly into the focuser without the 2" eyepiece adapter to reach prime focus.
The T-adapter also makes doubling the focal length by inserting it into the Barlow easy.