Another advantage of these shoots is that if you have a large nep that is making boring uppers (for most species, lowii not included) then these basals will produce lowers for you, which are in general much more impressive/larger than uppers.
I normally wait until the shoot has atleast 3-4 open traps before I take a cuttign from a basal, I find the success rate is dramatically increased, also depending on the nep you can either place the cutting in pure H2O, in a spag/perlite mix, in a peat/sand mix or use root hormone.
E.G I have found that ampullaria cutting do best in the peat/sand soil with no hormones, but maxima rot in the same mix and do best in an airy spag/perlite, I can't say much about hormones as I have always used them with success however some say they inhibit the plants natural root hormones.
The big thing with cuttings is high humidity, stable temps, moist soil and bright light (similiar to the parent plants), and obviously the larger the cutting the greater the chances, also certain species are more prone to failure.