  Two effects are identified that affect the visibility of the Mott transition
in an atomic gas in an optical lattice confined in a power-law potential. The
transition can be made more pronounced by increasing the power law, but at the
same time, experimental uncertainty in the number of particles will induce
corresponding fluctuations in the measured condensate fraction. Calculations in
two dimensions indicate that a potential slightly more flat-bottomed than a
quadratic one is to be preferred for a wide range of particle number
fluctuation size.
