I defined dhcpcd_eth0="-t 6" in /etc/conf.d/net but the dhcpcdc timed out after 12 .0xxx sec - got several times this value by prepending the command 'time' in /etc/init.d/net.eth0 in front of the chcpcd call : time ${conf[0]}_start "${iface}" ; x=$?
This should be fixed in dhcpcd-3.0.0