Bridge Placement for Proper Intonation

Hello, this is always something I've had to relearn on every single dulcimer I build, through trial and error. I'd love for it to be put in succinct terms for me. If I tune my melody string to D and the octave is exactly 0 cents off, then decrease my VSL, by bringing the saddle closer to the nut, then retune the open string to D,  should I expect the tuner's reading at the octave to be higher or lower pitch than D. Will it be some cents above or below?
This would be very useful information for me since every time I've built a saddle yet I've just had to throw everything at the wall and see what sticks.

Thanks y'all
-Nate