Dave47tuc recently bought a 2 inch barlow that he seems quite happy with.
He wasnt impressed with the gso 2 inch barlow.
http://www.iceinspace.com.au/forum/s...ead.php?t=2395
FWIW the 40mm gso wont be of much use in your scope unless its barlowed and then eye placement may be difficult due to the eye relief being extended by the barlow.