Hi,
I stumbled upon the same problem. The script from bonsak didn't solve the problem for me.
But thanks to a tip I found a working solution.
It is possible to make a parent-child setup. But you have to change the values in the parent settings after creating the child settings.
import c4d
from c4d import gui
import redshift
def main():
#Create main render setting
rd = c4d.documents.RenderData()
rd.SetName('render_group')
rd[c4d.RDATA_RENDERENGINE] = redshift.VPrsrenderer
rd_red = redshift.FindAddVideoPost(rd, redshift.VPrsrenderer)
doc.InsertRenderData(rd)
#Create child render setting
child_setting = c4d.documents.RenderData()
child_setting.SetName('child setting')
child_setting[c4d.RDATA_RENDERENGINE] = redshift.VPrsrenderer
doc.InsertRenderData(child_setting , rd)
redshift.FindAddVideoPost(child_setting, redshift.VPrsrenderer)
doc.InsertRenderData(child_setting , rd)
#Change main render settings
rd[c4d.RDATA_XRES] = 1920.0
rd[c4d.RDATA_YRES] = 1080.0
rd[c4d.RDATA_FRAMERATE] = 25.0
rd[c4d.RDATA_FORMAT] = 1023671 #PNG
rd[c4d.RDATA_FORMATDEPTH] = 1 #depth 16bit
#Change Redshift post effect
rd_red[c4d.REDSHIFT_RENDERER_ENABLE_AUTOMATIC_SAMPLING] = 0
rd_red[c4d.REDSHIFT_RENDERER_UNIFIED_MIN_SAMPLES] = 32
rd_red[c4d.REDSHIFT_RENDERER_UNIFIED_MAX_SAMPLES] = 256
rd_red[c4d.REDSHIFT_RENDERER_MOTION_BLUR_ENABLED] = 1
rd_red[c4d.REDSHIFT_RENDERER_COLOR_MANAGEMENT_OCIO_VIEW] = 'Un-tone-mapped'
if __name__=='__main__':
main()