I strictly use LR901's in my AVS (modded cartos in my AFSv2) and it works to MY taste for sure... I mostly use the not-so-ever talked about AW 18490 HD
batteries (MY personal favorite TS config) for a good days worth of
vaping...
I do use the AW 18650s HD as well, not only on the GGTS but other mods as well, and they last me approx 2 days.. (my
vaping habit is inconsistent though these days.. so I can't say how it would compare to how I vaped months ago

)
I haven't used ultrafires for some time but I have UF 18650 2400mah protected batts that DO fit in my TS... I would like to note I have the earlier batch TS BUT replaced the brass tele-shaft with the aluminum one that I believe is the same tele-shaft the current TS'es use so with that in mind I would imagine these will fit in the complete current unit.....
my usual disclaimer: some of my comments might be redundant, but I still put it out there
just in case
Thank you
LGD