If the tempo map ramps, you need to acidize the guitar and bass files, which is a whole other learning curve in itself.
If the tempo map jumps from one tempo to another, you can slip edit a clip edge while holding Ctrl to get the clip to conform to the new measure length caused by the tempo change. Don't forget to do an offline bounce after stretching a clip to apply a high-quality offline pitch tranposition.
You can use the slip edit technique on small jumps to create the illusion of a ramp.