From feedback from other posters I think that at +/- 5'9" (barefoot) and 30" inseam, I may be too short for using a GSA on more technically challenging terrain. I am looking to do some long, cross country trips in developing countries:

My riding will be:
-On pavement (But-poor road quality common to expected in sections) 50%
-Dirt roads 30%
-Poor dirt roads, washed out in places 20%
-Developing countries
-Poor fuel availability, variable quality

Right or wrong I have a lot of confidence with BMW Boxer reliability, basic maintenance and feel comfortable with the riding position. So (I think) want to stick with a BMW.

GSA-Pro +
-A Boxer!
-Large tank, long range
-Spoked wheels
-Low gearing
-Stocked with extras
GSA-Con -
-Very high seat height

GS-Pro +
-A Boxer
-Lower seat height
GS-Con -
-Cast rims, prefer spokes
-Need to add lots of extras (standard on GSA) to get it tour ready

F800GS- Pro +
-Off-road round the world capable (still to be decided?)
F800GS- Con -
-Not a Boxer (Is this still relevant?)
-High seat height
-Small tank

With the above in mind am I better off ??:
-Buying a GSA and making it lower?
-Buying GSA and learn the Flamingo
-Buying the lower GS and adding large tanks and extras?
-Buying another non-BMW bike?

Appreciate all the advice, feedback and comments from people that have earned their experience the hard way.