Wow, I never would've thought his topic would grow like this. Interesting comments scattered throughout.
I am a Carpenter (mostly) who tinkers in the direction of Timber Framing, so my perspective is a little different, perhaps.
My Sawhorses are built with 30" pcs of material cut with a compound Mitre/Bevel angle so that when assembled, the legs splay out at 15 degrees in both directions. They are stable on flat surfaces and are forgiving on "lightly" un-even surfaces as well.
Unlike Northern Hewer, I prefer to overhang the top rails. The trick there is to not overhang past the position of the splayed foot of the Horse, otherwise, tipping conditions exist if the overhang extends past the "Pivot" point. (Yes, there was a steep learning curve)
The 15 degree angles involved in cutting and laying out the pieces are approximately a 3 in 12 pitch on a Framing square. (14 point something, close enough)
And yes, they are good for cutting material with a power hand saw, but too high for working Timbers. Layout is okay at this height.
My last comment would be to find a couple strips of used carpet to use for "horse covers". Put the carpet on top of the Top Rails before setting down finished material on the horses. Nothing worse than an unseen staple or nail/screw head to ruin a nearly complete piece.
