The 10, and the 10E, will not run PureSignal with an external feedback source without internal modifications.
And, wow, for the first time I am going to actually point back from the forum here to a thread on the old Yahoo Group!
https://groups.yahoo.com/neo/groups/apache-labs/conversations/topics/25764This is a lengthy thread, nearly 30 posts on the subject. The thread rambles around a little bit, but if you read all 30 posts the information is in there.
I don't own a 10E, but if I did, I would be inclined to modify K19 such that the side that is normally grounded is instead routed to an SMA on the rear panel. Then that SMA could be attached to the coupler output (through whatever amount of attenuation is appropriate for the power levels involved). With this setup I'd also put a 50 Ohm terminator on J5.
73,
Scott