Thank you for your quick replies guys. I just woke up (doh!) so I'll get back to you with all details shortly, but just to quickly answer axels question on olsr.
Ok I will also post my setup
Aa ----------------- Ba --------- Ca (a is 11a g is 11bg interface) 184.108.40.206/24 220.127.116.11 18.104.22.168 Ag ----------------- Bg --------- Cg 22.214.171.124/24 126.96.36.199 188.8.131.52
11a is switched OFF on all nodes.
OLSR seems to ALWAYS just go from Ag directly to Cg (I presume it's because it can see it on g radio) even though route through Bg would be better and it takes 10-15ms (at least for traceroute output). B.A.T.M.A.N ALLWAYS goes through Bg and it's all 2ms hops Ag > Bg 2ms, Bg > Cg 2ms. Much better wouldn't you say? That's why I've given up on OLSR.
Ok that was the short answer, later I'll get back to you on the gate0 issue.
but I believe this would be a far more usable setup than olsr 5.3 that I also tried.
maybe check 5.4. Because I think that the improvements from 5.3 to 5.4 are huge, but also because I am always interested in the concrete pros and cons that people observe between the latest olsr/batman state-of-the art.