If I put the deflexed limb on the bottom and tillered it 1/8" positive, my limb timing would be ALL screwed up.
I don't think it matters much where it's put if you tiller the bow so that the limbs are synchronized... instead of to a predetermined measurement. If so, and the deflexed limb is on the bottom, you'll likely see a negative tiller. If made so the top limb is the deflexed one, you'll end up even or positive at brace... depending on the degree of disparity between the limbs... and bow design aspects like location of longitudinal center.