Flats can be tricky to nail and with fat-off even harder. I usually try to avoid wrapping but in this case it might be the safer choice. Lower cooking temps would be good - below 250F if possible You might pull at 180F or so and wrap in foil with your favorite basting liquid.
What kind of cooker are you using? Regardless, I recommend keeping the lid closed on your cooker through the cook if possible to keep temperatures and moisture up.
Rob - 26-1/2" OTG and A Clutch of BGEs