Dormouse,
I use LR901's on Mini 901 and KR8 Batts, I keep 5 of them in a PC and have a separate charger to charge them, I get about an hour out of each Batt, I have had them in use for over 6 months now and haven't burned out a one. It's a great little setup for stealth vaping, so in fact you can use a lower mAh Batt with an LR set up, it's just how long will it last and as cheap as these style Batts are now I actually love this little set up some times, it's cool to go back to the old days and yet still put out plumes of vapor with the old style Mini Batt, I also have been running the newer Dual Coil Carto's on these little mini low mAh Batts and they kick out some great flavor and vapor too. I think the real trick is not over heating them and burning up the connection wire from the button to the Batt connection, as long as you dont chain vape them it's all cool. In fact the only reason I even tried this was because I had about 15 of these Batts that where new, never used I found tucked away so I decided to experiment with them and an LR anything on them, to my surprise they have been going for 6 months now on a daily use. Just saying, ya know