This is the bike. You can see from the angle of the RD that there's too much chain. It ought to ideally be at very close to that angle when I'm in my smallest cog, but I'm a fan of big-big combinations on the local hilly roads, so it works well in combos like 50x28, which I use a lot.
A mechanic at a bike shop I knew, said that's how he adjusted chain length, was put it in the smallest cog and the biggest sprocket, and the RD should be right at the middle of its range of travel, IIRC.