(for mixing) I bring in the reference track in 'Track' then move it to Reference Buss and then do 'Exclusive Solo' between 'Mix Buss' and Reference Buss. Is that the easiest way? The reason i am asking is, Exclusive Solo does not always work in this process flow. 
 
Would love to know how you do it. 
 
Thanks in advance. 

I create a Reference Bus which is after my Master Bus. It's just a pass through to allow me to compare what's out of my Master Bus compared to reference tracks.

I get whatever reference tracks I need using the tool in this link.

https://www.samplemagic.com/details/184/magic-ab

I put this on the Reference Bus. When I'm not using it it's off and nothing effects the signal reaching the audio interface.

It's great!

Magic AB is great, as is Melda MCompare. They both do roughly the same thing, so I'd try both and see which you like. If you like the Melda tool it'll probably go on sale in a week or two. Every week they offer 50% off 5 of their plugins.
 
Dean

I create 2 busses: Meters and Master, and the Master is fed into the Meters buss which goes to the hardware outs. On the Meters buss, I have various metering plugins so I can see what the audio is doing.
 
I run all of my project tracks to Master buss and put any effects I require on that.
 
Then I set up a track with the reference mix in it and set the out of that to the Meters buss directly.
 
I usually switch between them by soloing/muting the reference track.
 
Some caveats to keep in mind is the reference track is usually already mastered so you'll likely need to drop the output of that a fair but to match your project, unless you're running mastering effects on your Master buss already (it's actually sometimes a good idea to mix into a limiter so you can get an idea of what might change once your mix has been sent off to a mastering engineer and had compression applied, etc. - just remember to mix with the limiter off when you prepare the mix for mastering!)
 
There's probably better ways to do this stuff out there (see the post above for a good example) but I tend to find this is the most efficient for me. 

I create a track for the reference song and route it directly to a hardware out.
Then I mute the track and create group for Mute and Solo buttons.
 
Solo button down: only reference track is heard.
Solo button up: now track's mute button goes down and reference track is muted.