after a successful trial of tpu tubes i've got a further dozen, for the bikes that may need/use them. i've been also trialling tubeless tyres without sealant (or with a bare minimum, if they didn't hold pressure dry) for the past year, done the pbp qualifiers and other long rides with tyres like that. the reason behind it is, if there's a puncture, there's no mess to deal with when putting the tube in. if a puncture is small, there's still an option to put sealant through the valve, which is quicker vs inner tube.
looking after multiple bikes with tubeless tyres is a bit tedious, having to track and check when the sealant was last added and topped up. so this new approach works quite well for me and tpu tubes are a welcome addition to the system, along with the tyre plugs, sealant, valves/cores, glue, patches and boots.
i'd still be running 50-60ml of sealant for very important rides/races where stopping is best kept to a minimum.