Light tires/ tubes combo - my experience...
I had Conti twister supersonics (360gr) and schwalbes xxx light tubes (100gr). I did on them 1000miles. My experience - about 15 flats overall - on average every 66 miles I had a flat. I had enough of it (6 flats last month - and its quite cold here right now - my riding buddies were quite pis..d at me also because of my flats, which I understand) and am going to change the tires into Cont twister pros foldable - (450gr) - with better protection against flats.
What is intersting, when you look at the light bikes sites - most of the times the use conti supersonics and light tubes - you start asking yourself a question - do they ride the bikes at all?
Conclusion - It is difficult to be a weight weenie
(lots of time for patching flats and lots of cash for parts replacements)
my few cents...