Once I recorded a guy who was so consistent in his singing and playing that we actually couldn't tell the difference between 2 takes. I finally pasted them on different tracks and lined them up together to compare. At first I thought I'd just made a copy of one track, but they were slightly different.
That is rare. And when you are stacking vocals or layering guitars it's not uncommon that you have to massage the tracks a little to make everything line up right.
One solution with guitar parts is to feed the signal from the guitar into several amps at once. The resulting tracks will line up perfectly and each amp delivers it's own unique sound.
But you can't just use a splitter cable, and even pedals with multiple outputs can be a problem if the outputs aren't isolated. Nasty hums and ground loops can result. Lift the ground from one of the amps and you could get a shock when you touch your mic.
There are several boutique solutions, some with 5 or more outputs. But they can be expensive, and do you really need that many outputs? Through guitar playing friends I found a simple fix. Google "Lehle" and you'll see several solutions.
We've used the P-Split and the Dual Amp Switcher. the Dual also has an output to feed a tuner. The best thing about these splitters is the high quality isolation. Your tone is preserved and noise floor kept as low as possible.
Stacking or blending tones is not new, but there are smarter ways to do it. Get the best sound you can and do it safely. You're welcome.