You sound as if you are getting on great! I agree with Taz and Willow Flats on the touch and treat system. The best advice I got was 'be clear with your asks and rewards so they associate to it better'. So, I would touch for a second or two, take my hand away and reward immediately with praise and a treat. Then do it again, and again, and again... All fairly close together and for a short period of time e.g. 10-15 min sessions.
You'll know when you're ready to move to another area when they show absolutely no signs of stress on the area you are working on e.g. no flinching, moving back, or ears back in defence. Sometimes they may even start to get a little curious/cheeky as they associate that action with a treat. Mine would begin to look for the treat and get a little cheeky demanding it lol. While great to see the confidence growing in them I knew that was my signal to stop giving them a treat for that action, I'd give verbal praise and a nice rub instead.
I was advised to just work on one area until they were completely happy before I moved to another but do what is comfortable for you and the horse. I worked on getting them used to me touching them around their head, then onto the feel of the lead rope, headcollar training, being able to put the headcollar on and off, spending time clicking the lead rope on and off etc. All until they were completely calm with each move. If they stressed too much on a new move I'd just go back to the last step we had mastered for a few times to rebuild their confidence and then try the new area again. I hope that makes sense! Baby steps and patience but it sounds as if you're off to a great start!