You sound like you desperately don't want big heavy slow tyres.
Personally I wouldn't jump into the bigger 700g ish tyres unless you consistently ride in rocky areas (peaks/lakes etc etc) or sessioning DH courses and want all the cushionining you can fit
Something like:
2.1" Kenda Blue Groove(slightly chunkier) or Nevegal(still chunky) DTC folding is 609g (I'm running Nev's front/rear atm). They are near as makes little difference as big as a Maxxis 2.35" High Roller/Minion/Ignitor/Larsen TT and bigger than continental 2.3"s (SK's) and have coped no problems with lakes(borrowdale/walna scar)/peaks(j.ladder)
2.2" Bontrager ACX folding is about 565g and bigger than a 2.1" Kenda. They are a little hard though
re: tyre sizes
IME/IMO
IRC 2.1" ~= 2.1" Maxxis Ignitor/HR = 2.1" Continental < 2.1" Panaracer << 2.3" Continental (SK's) = 2.1" Maxxis Advantage/Crossmark < 2.1" Kenda < 2.35" Maxxis = 2.2" Specialized < 2.2" Bontrager << 2.25" Maxxis = 2.5" Maxxis = 2.3" Specialized = 2.35" Kenda
(Open to discussion .. especially as to where 2.2"/2.4" Continental and 2.35" Panaracer fit into there)