As long as it works, no preference. The Morgan Carbtune packs away nice and small. A set of four vacuum gauges is cheaper but bulkier, just match the readings (connect all four to a single vacuum source and set the dials to read the same). The mercury carb sticks (if still available now that mercury is too dangerous for we civilians to handle) work great but must be kept standing up or the mercury spills out.
Other methods are discussed here now and again. I haven't read of one that sounds workable yet. I think you need four independent vacuum measurements.