  We develop new methods to study the properties of galaxy redshift surveys and
radial peculiar velocity surveys, both individually and combined. We derive the
Fisher information matrix for redshift surveys, including redshift distortions
and stochastic bias. We find exact results for estimating the marginalised
accuracy of a two-parameter measurement of the amplitude of galaxy clustering,
A_g, and the distortion parameter beta. The Fisher matrix is also derived for a
radial peculiar velocity survey and we discuss optimisation of these surveys
for equal timescales. The Fisher Super-Matrix, combining both surveys, is
derived. We apply these results to investigate the 6 degree Field Galaxy Survey
(6dFGS), currently underway on the UK Schmidt Telescope (UKST). The survey will
consist of approximately 125000 K-band selected galaxies with redshifts and a
subset of around 15000 galaxies with radial peculiar velocities. We find for
the redshift survey that we can measure the three parameters A_g, Gamma and
beta to about 3% accuracy, but will not be able to detect the baryon abundance,
or the matter-galaxy correlation coefficient, r_g. The peculiar velocity survey
will jointly measure the velocity amplitude A_v and Gamma to around 25%
accuracy. A conditional estimate of the amplitude A_v alone, can be made to 5%.
When the surveys are combined however, the major degeneracy between beta and
r_g is lifted and we are able to measure A_g, Gamma, beta and r_g all to the 2%
level, significantly improving on current estimates. Finally we consider scale
dependence of r_g and the biassing parameter b. We find that measurements for
these averaged over logarithmic passbands can be constrained to the level of a
few percent.
