Definately a Halti and when he puts his head down ,lift it up and say No. (I often have had my neighbours golden lab who is digital and pulled like Hell when young).
Walking backwards is a known training excersie. We did this when our lab was young. He walks with out a lead, well used to but now on a lead on the lane as he is now deaf and almost blind so can be a bit unreliable in his old age at 141/2
Terrie if I put the lead on my lab as you say he justs stops till you sort it out. (Mine is a black lab and Analogue i.e. wind him up to get going )
But sally will just step over the lead herself.
oldbee