one just creates the targetlv in the same size as the srclv (8g in this case),
and when telling pv this size for the transfer it shows all the bells and
whistles it can .. even ETA :_)

dd if=/dev/srcvg/srclv | \
pv -p -e -t  -r -a -s 8G | \
ssh -i /home/user/.ssh/sshprivatekey -C -c arcfour -l root 172.x.y.z 'dd of=/dev/targetvg/targetlv'