By semi-slick I mean full-on semi-slick, Continental Cyclocross Speed... actually measure around 39mm wide. Running tubeless I can take these down to 30-35psi for improved comfort and traction. I feel like these are actually overkill for your standard limestone trails as far as width and weight are concerned, but they are flexible and work well on a variety of surfaces:

The other option I'm considering are the Stan's Ravens 2.0 and 2.2... the tread on these is shallow but I'm sure it would be enough to slow me down on limestone:


Alternately, I could be an Luddite caveman and run tubed tires. In the front I have a nice WTB Vulpine 2.0 who's only real downfall is that it is explicitly not tubeless compatible:

For the rear, I could do my very, very heavy Continental Country Ride, measuring in at 46mm:

That adds a pound over the Cyclocross Speed tires and only 6mm wider, so, never mind. Great touring tire though.
And I also have an IRC Mythos CX 42c, which also requires a tube and I'm thinking is too knobby for these purposes, unless it ends up muddy and greasy next weekend:
