At the grate I would prefer it to be around 240-250.
I decided that 260 was ok since I was doing butts. I went to bed at 1:00 am. After 3 hours my maverick went off alerting me that the temp pit temp was at 205. I had one vent closed and two barley open with the exhaust 100% open.
I opened the vents up 100% until it had bumped back up to 230. I shut one vent off and closed two down to a little less than 1/4 and went back to bed.
Two hours later my maverick alerted me ( actually, it alerted my wife who them alerted me ) that the pit temp was at 300 and climbing fast.
After some time I got the temps below 300 and falling slowly, so I went back to bed and at 8:30 the temps were still at 269.
Had this been a brisket cook I would be not be very happy.