My first post, so go easy on me

I was recommended posting about this here from the folks on Singletrack World. Anyhow, I have a few questions on the AlpKit bike packing kit as I'm intending to do some multi-day trips on Dartmoor after my final uni exams in May before leaving Plymouth, as well as LeJog over the summer.
First up, anyone running the framebags with a large 29er on-one inbred? I'm not sure what width to go for. The bike is currently running 1*10, but I'd like to have enough clearance for the option of running a granny ring while touring. Would I get away with a 6cm framebag? I'd obviously like the largest possible for more carrying capacity. Anyone care to comment on any upgrade options they went for? I'm thinking of upgrading to the surgeon opening.
How stable is the Koala seat pack? Do those using one find the unit reasonably stable, or that it constantly moves around, or restricts movement at all?
Also after general feedback of how people find the Kanga? Does this interfere with brake levers, shifters, etc?
Cheers,
Dan.