Bypass the plug-ins temporarily. Bus the track that you want to measure the latency of the plug-ins on out to a new audio track, and record the result. Zoom in real close to look at both tracks to see how far behind the the new track is compared to the original. Then nudge the original track back by that same amount to acount for the latency of the plug-ins. Make sure to make a duplicate playlist of the original track before you start moving it around so you can go back to the original quickly. Also, here's a for some plug-in measurements I took, but it was for PC so I'm not sure if the latency is the same on mac. If it's not the same, start compiling your own list of the plug-ins you use frequently. This will speed the whole nudging process up for you in the future.