To do that, I would use a couple steps.

Set time signature to 6/8.
Record the track.
Open the ACW and tell it you want to use the current file and to create the Tempo Map (it defaults to not changing the tempo map during the popups so pay attention as it opens)

Use the ACW to set the Tempo. Do this by playing the song and tapping the F8 key on the 1st beat of every measure; you'll see the measure lines adjust.

Once 'close enough' with the tempo map click Send to PT (or RB or BiaB).
Now check the notation.
If needed copy the track to another blank track and quantize that track (Edit-Quantize)
This brings the notes closer to the nearest beat (or 1/4 or 1/8 or 1/16 or 1/32 depending on settings).
Check Notation again.

Using Quantize on a copied track and viewing the notation for that track (but listening to your original) may 'correct' the notation timing without affecting the actual performance on what you already have recorded.
But if you intend to wander with the tempo it's better to set the tempo map later using the ACW and then go from there. I do this on 'live' recordings when I want to add Realtracks and I need a tempo map.


I do not work here, but the benefits are still awesome
Make your sound your own!