FTSAW immunoassays accelerate the process of measuring immune reactions by actively squeezing target-containing microbeads to the interrogation region. In this paper, we develop a normalized enrichment kinetics analysis for human IgG by simultaneously considering several key metrics: RF power response, blank retention, 60-s captures count, time required for detection, signal to blank ratio, concentration-dependent scaling, and chemistry-selection dimensionless indices. To construct our mathematical design parameters, all FTSAW data presented in this paper was numerically transformed into a minimal set of quantities. From our analysis, it appears that the sandwich configuration lowered the 60-s blank count from 27 to 4 microbeads, increased the signal to blank ratio from 3.07-18.96 to 5.00-90.75 depending on the concentration range, and sped up the detection time 82.9% at 100 ng/mL and 48.9% at 10 ng/mL in comparison with the direct antibody-antigen capture. The latter configuration had greater blank-corrected counts for all concentrations considered. Our analysis reveals three distinct crossovers: timing crossover near 0.55 ng/mL, early utility crossover near 5.6 ng/mL based on neighboring measurements, and selectivity-weighted throughput crossover near 0.65 ng/mL taking into account blank suppression explicitly. The RF power response analysis indicated a dominant acoustic gain between 0.1 and 1 mW, followed by diminishing returns at high powers. Thus, this work answers the design problem by providing concentration-dependent optimal FTSAW assays choices: sandwich assays for fast low-background detection at moderate-high concentrations, and direct capture configuration close to the lowest considered concentration due to higher event counts.