I bought the LT-104 and Burris XTR set as listed on their web site, and there is not enough eye relief on a NTCH view when it's mounted on my flat top. Now, I don't have a forearm with rails, and the LT-104 hangs over the front of the receiver by a notch.
In 1X, it still works. In 4x, I need to back off a bit to get a clear sight picture. With an A1 buttstock you're turkey-necking a bit to get your sight picture.
SPR-E (AKA the LT-139) is probably the best bet if you don't have rails to move forward on.