  We conduct an analysis of the measurement abilities of distinctive LISA
detector designs, examining the influence of LISA's low-frequency performance
on the detection and characterization of massive black hole binaries. We are
particularly interested in LISA's ability to measure massive black holes
merging at frequencies near the low-frequency band edge, with masses in the
range of $\sim 10^6-10^{10}M_\odot$. We examine the signal-to-noise ratio (SNR)
using phenomenological waveforms for inspiral, merger, and ringdown over a wide
range of massive black hole binary parameters. We employ a broad palette of
possible LISA configurations with different sensitivities at low frequencies.
For this analysis, we created a tool (github.com/mikekatz04/BOWIE) that
evaluates the change in SNR between two parameterized situations. The shifts in
SNR are computed as gains or losses as a function of binary parameters, and
graphically displayed across a two dimensional grid of parameter values. We
illustrate the use of this technique for both parameterized LISA mission
designs, as well as for considering the influence of astrophysical parameters
on gravitational wave signal models. In terms of low-frequency sensitivity,
acceleration noise or armlength is found to be the most important factor in
observing the largest massive black hole binaries, followed by break frequency
and then spectral index. LISA's ability to probe the astrophysical population
of $\sim10^7-10^9M_\odot$ black holes is greatly influenced by these aspects of
its sensitivity. The importance of the constituent black hole spins is also
highlighted.
