My common vray renderer setting.

I usually use this setting when I work with vray in 3DsMax for rendering transparent object.

global switches = turn off default lights
image sampler = adaptive QMC
antialiasing filter = mitchell netravali
indirect illumination = on
secondary bounce = QMC GI and multiplier = 0.8
refractive GI caustics = on
irradiance map settings =
--custom min/max = -4/-3
--HSph subdivs = 20 = interp samples
--clr = nrm = 0.4
--dist = 0.1
environment =
--skylight = pure white color, 0.1 multiplier
--reflection/refraction = pure black,1.0 multiplier
QMC sampler = noise threshold = 0.005