Question About Levels In a Mashup

Hi, I also asked this over on r/edmproduction but I figured since you all are specialists in this field I might get some more focused responses here.

I have a mastered acapella and instrumental which both peak at 0 db at peak points. Due to this, I lower the instrumental volume and acapella volume in order to mix them effectively and not put out a hot signal. Although the vocal will now sit well with the instrumental while playing, how does one then make up for the lost volume in the instrumental when the acapella isn't playing? I usually use and Invisible Limiter set to stop any peaks on my master but I assume compression should be used? How would I use it effectively?

Thank!