EXS 24 Logic Sampler Users Group

I was wondering if anyone has an tricks of the trade w/regard to timing of 
samples within a tune. I'm having difficulty synchronizing everything. The 
best thing I can think of is to set a guide track in an audio track of one 
sample, determine the exact tempo by pressing the "T" key and then looping 
it. This would be the "master" loop for a particular section of a song from 
which other samples from the same source (sampled tune/groove), even if a 
little off tempo wise, can be played over (just so long as they aren't 
played for very much time - at which they would fall out of sync w/the 
master sample). If you move on to another "master" sample within the same 
song, you determine that sample's tempo and change the tempo in the tune to 
that new tempo. Does this sound right? Does anyone have any 
knowledge/experience to share with regard to this? Are there any good 
sources online to read about such things? Many thanks,

Pete