That's one gorgeous bike. I agree with above- DT shifters look best. But in this case function has to come first. Because the bars are same height as the saddle (nothing wrong with that) it will be more to reach DT shifters than a typical drop bar bike (picture supporting your weight with one very flexed elbow). Light Action thumbies are a real pleasure to use- very little force and predictable gear changes. Thumbies by nature require some awkward motion of the thumb though. So thumbies are your best bet IMO since stem mount and bar end are off the table. Oh and trigger shifters just don't belong on that bike.