Oops my bad, the Samp function is called Universal HQ time stretching. Elastic Audio is similar but designed for changing the timing and pitch and duration of individual phases words or notes like Melodyne. The time stretching function is simpler and better suited to this. It has several different algorythms and ways of doing it, but the Universal HQ setting is the best for stretching complex audio transparently. I do it at the object level by selecting the entire track as an object and entering a new desired length. You can work in whatever units you want- time, samples, etc. (it displays the current length and you enter a new one, or I think you can also grab the edge of the object, stretch it and snap to a marker that is aligned with an event on the other stereo track.
I've stubbed my toe on Samplitudes learning curve at times, but time stretching one file to match another is delightfully simple. I found it hard to belive it was that easy.