Control, another aside.
I just looked at the gearing chart of one of my bikes, a commuter which is an old hybrid with a cheap 42/34/24 crank, and 7speed 11-28 on it. Its top gear of 34-11 on 700x35 is almost exactly your setup, at 84g.i and as I rode the bike a lot this year, I know that I regularly ride it at 84 g.i to about that 35-40kph speed you mentioned (22mph/35kph at 90) in the mid ring, too lazy to change to the 42 tooth on the short downhills on my commute.
All I can say is that from my touring experience, the times you actually go faster than 30kph are not that often, so with the limitations of a double, and the fact that you say you arent into going fast down hills, this will be fine--especially when you take into account that 90% of the time, you'll be completely in the 10-25kph range.
I'd say its way more important to figure out your equipment amount, how it will pack on the bike well, and what stuff you want and need to be comfortable, no matter what others use and suffer through. Not to mention just getting out and keeping active so that you have a good physical base come spring for bike training if you are able to fit the divide ride into things next year. Not to mention just a lot of riding on diff surfaces and such to maintain or improve your bike handling skills and reactions.