I use batteries according to build and I stay around .20 to .35 ohms on my builds. The Sony VTC5A and theSamsung 25R are both good batteries.
The topper that comes on the 160 is terrible IMO. There is what they call a filter for it which is simply a spit back guard. Its disk shaped and fits into the underside of the black drip tip. I highly recommend using it until you find a good topper.
I have too RDAs on the way, the Goon and a Haladay clone. Got both from 3FVape and I did happen to catch the sale on the Goon. The Haladay is single coil. When you look for an atty for it look for ones with the BF pin in the description. A few
Halady clone 22mm
Goon 24mm <----- will have some slight overhang
No Legal clone
And anything that @Rob62 or @ozo recommends. There are others that know which ones to get but I just named a couple of folks that have helped me.