When my Racepak gives me accel G, it's basically telling me the angle of that weighted string in relation to it's vertical at-rest position. Linear accel + pitch rotation. Actual force of the weight pulling on the string @ 1G accel would be about 1.4 x it's static weight.
The old G-tech that I used years ago had a G correction factor you could change to account for different amounts of pitch rotation, but the Racepak does not.
Grant