I think you bought the ideal focal length for macro. I have a Tokina 100 2.8 that I purchased in 2011 that works great on my D7200. DX gives it a bit more reach and more DOF than shooting on my FX body. Most times I'm using a tripod, shutter release and MUP, with a small aperture (f/8 or lower)...
I've used the regular Eneloops for years in my 3 SB-800s and SB-500 and see no need to change. I recharge with this Watson unit. Allows you to drain and fully recharge the battery.