Simsi - 8:35 pm on Aug 1, 2013 (gmt 0)
I no-index pages that have niche value, especially if there isn't much text on. Haven't seem any negative implications from that.
Guiding Google: the way you link internally will do that and also tell Google what you consider important. A sitemap is worth doing with dropdown navigation just as a backup but you'll probably find G has no issues following that either.
Submit the sitemap to WMT too if yo want to play it safe.
I think what you are doing is sensible myself...been through that loop myself and it seemed to pay off.