You're right about high compression needing less advance, but the unit does not come in two versions.
I set mine up with a timing light so it gives the maximum desired advance at high rpm; it's been a while since I fiddled with it, but I believe that this means ignition is retarded relative to TDC at very low rpm. ALSO, I've set mine up so I have some wiggle room (3 clicks of retard) allowing me to play the role of human vacuum brake on the advance, if I'm pulling a hill in an awkward rpm range for down shifting. Here's a photo of the little clamp I use to prevent accidental over-advance.
Steve