Just reading this - thanks to finding a cheap-copy, and a recommendation from Jedburgh.

It contains an extract from the Middle-East 1918 Intelligence Handbook,

The Arab Bureau was really a Tribal Department where all the information about tribes was recorded, and which also compiled and issued various analyses of tribes, genealogical tables, tribal maps, personalities and who's who and so on...

...so basically given that this is provably a military G2 area, and, as I have said, always has been, so why the HTT route?

...and as one reviewed notes here, HUMINT can be massively over played.