  We present new measurements of the projected spin--orbit angle $\lambda$ for
six WASP hot Jupiters, four of which are new to the literature (WASP-61, -62,
-76, and -78), and two of which are new analyses of previously measured systems
using new data (WASP-71, and -79). We use three different models based on two
different techniques: radial velocity measurements of the Rossiter--McLaughlin
effect, and Doppler tomography. Our comparison of the different models reveals
that they produce projected stellar rotation velocities ($v \sin I_{\rm s}$)
measurements often in disagreement with each other and with estimates obtained
from spectral line broadening. The Bou\'e model for the Rossiter--McLaughlin
effect consistently underestimates the value of $v\sin I_{\rm s}$ compared to
the Hirano model. Although $v \sin I_s$ differed, the effect on $\lambda$ was
small for our sample, with all three methods producing values in agreement with
each other. Using Doppler tomography, we find that WASP-61\,b
($\lambda=4^\circ.0^{+17.1}_{-18.4}$), WASP-71\,b
($\lambda=-1^\circ.9^{+7.1}_{-7.5}$), and WASP-78\,b
($\lambda=-6^\circ.4\pm5.9$) are aligned. WASP-62\,b
($\lambda=19^\circ.4^{+5.1}_{-4.9}$) is found to be slightly misaligned, while
WASP-79\,b ($\lambda=-95^\circ.2^{+0.9}_{-1.0}$) is confirmed to be strongly
misaligned and has a retrograde orbit. We explore a range of possibilities for
the orbit of WASP-76\,b, finding that the orbit is likely to be strongly
misaligned in the positive $\lambda$ direction.
