Well, hmmm, you don't seem to certain as to the timing and all the variables of this particular cook, so under the circumstances it kinda sounds like a crapshoot either way.
I'm with you on the dry turkey too, really not to good that way.
I'm kinda with aawa here too, leaving a cooker unattended for 3-4 hours???? not something I would be comfortable with personally.
I guess if you are really set on the turkey, then the night before sounds like your best option.
Good luck, let us know how it comes out,
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