LIterally just play AR9 NM maps. Don't make it complicated by adding DT to the mix if that's what you're going for.
Only reason to do that is to play AR9.5+ without dealing with 5*+ maps (because AR8-9 maps w/DT are the only way that happens). I still find it sad there aren't many AR6.6-6.9 maps to use HR instead, but what can you do?
(seriously, am I along in thinking that using HR to practice high AR (with lower CS/OD to compensate) is a lot better than using DT? Or is everyone else just a speed freak and I never got the memo?)