I'd get it as close to empty as you're comfortable with, fill it with 93 octane, then let that run through the system for 1/8-1/4 tank before loading up the tune. That way you know for sure, there's no 87 octane lingering in the system lol.
2012 Kona Blue 3.7L V6:
Borla LT headers, O/R h-pipe, Borla S-types, 3.73 gears,
Steeda adjustable UCA w/ mount, BMR LCAs, Airaid CAI,
LCA Relocation brackets, AE driveshaft, GT 80mm TB,
Black 18x9/10 2010 GT500 Wheels w/ Nitto NT555s,
Eibach Sportline Springs/shocks & Koni STR.T Struts