Weight wise they're not too bad at 850g.
For both that pretty good. For one, that's damn heavy.
They now make Smoke and Dart again (check panaracers website) and your Tioga Psycho's are available with a similar pattern by some other company.
I would be looking lightweight short nobbled tyres 2.1" to 2.3" size.
I know nothing of geax or maxxis though so cannot help, if you look elsewhere then Schwlabes website will help you through their tyres.
Look under All Mountain and the X-Country series as well as MTB (you'll see the list on the side and understand)
Rons and Nics are the ones I know, probably the Rons but not sure what loose gravel is like.. maybe ralphs..
The rest they'll be excellent at.
Conti's are probably similar if the tread looks similar.
The Scwalbe are much lighter than the Geax from what I can see on on-one.co.uk
Who knows as you say there are too many to pick from now
Check out some reviews on say CRC or Wiggle or singletrack, mtbr
Of course price will determine what you can buy, what are max. price are you looking at.