Oh poor you, that sounds really tough, especially with you going back to work. I know how hard that is - it's an emotional time and it'll be an adjustment for all of you. If it feels right to you to go back to putting a hand on him to calm him I definitely would. I'd try and keep it so that he's still going to sleep without your hand on him, but perhaps he's going through a developmental leap and needs some extra reassurance, or he's teething or coming down with something - or has picked up that a change is coming. If he needs a bit more reassurance I would give it temporarily. You could start with lying on the floor, go over to reassure him with your hand and then lie back down again when he's calmed?
I agree it's hard to tell if the longer A is helping. Are all his other A times the same? What does his day look like now? I wonder if he might do better with another A time being increased rather than the one immediately before bed?