Re: TDS & B&C reticle drop values?
FFP is a front focal plane reticle; its size increases or decreases as you increase or decrease the power setting of your scope. If I am not mistaken Goodgrouper was referring to people encountering problems when, being used to use the reticle for holdover at a certain magnification ( as is necessary in second plane reticles, whose size does not change), they could not use the magnification needed for the reticle. A FFP reticle will change its size but the holdover values for the different stadia remain constant.
As for yor question on the TDS reticle, if you aim at your target using any of the lines below the main crosshair you are aplying an elevation of xx MOA . I am not familiar with the INfinity program but for shooting LR you want a ballistics chart that tells you, among other things, how much elevation you´ll need to hit your target at xx distance, i.e.4 MOA at xx yds. SO to provide this elevation you can either use your scope elevation knob or use the reticle and hold for the 4 MOA you need. The problem with the TDS is that it does not use straight numbers, i.e. 2, 4, 6..moa.
In a FFP reticle, the stadia work well at any magnification; in a second focal plane, they only work well at one specific magnification.