  We investigate the absolute calibration of the Tip of the Red Giant Branch
(TRGB) in the Small Magellanic Cloud (SMC) using small amplitude red giant
stars (SARGs) classified by the Optical Gravitational Lensing Experiment
(OGLE). We show that all stars near the SMC's TRGB are SARGs. Distinguishing
older and younger RGs near the Tip according to two period-luminosity sequences
labeled A and B, we show many similarities among SARG populations of the LMC
and the SMC, along with notable differences. Specifically, SMC SARGs have
shorter periods due to lower metallicity and lower amplitudes due to younger
ages than LMC SARGs. We discover two period-color relations near the TRGB that
span all A-sequence and B-sequence stars in the OGLE-III footprints of the SMC
and LMC, and we investigate using periods instead of color for TRGB
standardization. Using variability derived information only, we trace the SMC's
age and metallicity gradients and show the core to be populated by younger,
more metal rich RGs. B-sequence SARGs yield both the most precise and the
brightest tip magnitude, and they are best suited for distance determination
and Hubble constant measurements because they correspond to the oldest stars
near TRGB. Assuming the geometric distance measured by detached eclipsing
binaries, the B-sequence yields the SMC's most accurate TRGB calibration to
date: M_{F814W,syn} = -4.057 \pm 0.019(stat.) \pm 0.029(syst.) mag (1.5% in
distance). Further study of SARGs will unravel the impact of population
diversity on TRGB distances and further improve TRGB standardization.
