‘I just looked up the Fulcrum 600db wheelset on the Merlin UK website & it appears they are for tubes only and not the “2 Way Fit” tubeless variant. If you like the lower rolling resistance of the Michelin Power Cup and your goal is to go faster, I would say you might need to accept the trade off of shorter rear tire life span in order to enjoy the sportier performance of the Power Cup. Plenty of bikeforums threads have discussed using Gatorskins for flat prevention/higher mileage but for many here, they will be of the opinion that the dull ride you get with a Gatorskin tire makes it a no go. If you are running butyl inner tubes with your Fulcrum wheelset now, you might try switching to latex inner tubes in order to lower the rolling resistance even more in order to see if you enjoy the smoother ride. Latex tubes are an inexpensive upgrade & when installed properly my experience is that they don’t get flats any more often than standard butyl inner tubes.

If you do go with a lighter more modern tubeless ready wheelset, if it were me I would not hesitate to set them up with some nice lightweight road tubeless tires of your choice. The newer wheels will most likely also have more internal volume (wider width) to accept 28mm or wider tires so long as your frame has clearance for this. To me a properly set up road tubeless wheelset is going to give you the sweet spot of all the attributes you could want: low rolling resistance, self sealing (potentially) for flat prevention, great grip in corners and on rough pavement and more comfort since they don’t have to be inflated rock hard.