Spur stop training should not effect the horse moving forward. In every spur trained horse I have ridden, both spurs on meant stop, left spur was used to pick up right lead canter and visa versa, when I wanted a flying lead change I changes which spur was on the horse. To back both spurs came off and I kind of sat down on my pockets and shifted my weight towards the back of the saddle. To move the horse forward I just squeezed with my calves.
Sydney, Appaloosa x Draft cross