Safety with R+
Of course we are going to eventually want to be in with them at some point. Rather than making yourself feel safe by asding restraints or tools to control the horse, protect yourself with things that actually help - like helmets and protective vests.
In training we can do a lot to promote safety too, many of us want to jump right to teaching fun stuff like running around together, cute tricks like spanish walk or fetch. But then we have hyper horses who throw hooves around and bite random objects. Why? Because R+ is a Strong and powerful training method and if you only use it to teach things like this, that's all you'll get.
We need to always, even with the safest horse, teach safe behaviors first. Let them learn stimulus control with safe behaviors. Teach behaviors which give you space and help you both feel comfortable moving together. A safe default "standing facing forward" is always a good early behavior to test your other behaviors. If they aren't sure what to do lining up in a safe default is always a good option. Practice this often and reinforce it heavily. You get what you reinforce.
Train away behaviors with the target before you train towards behaviors (for most horses) so you can ask them to move different parts of them away from you. Use a long target to guide behaviors and help the horse see what you are asking them to do. Practice sending to targets away from the handler and going around and object and back. This helps build you and your horse's confidence in being apart from each other and having more comfortable personal space.
Train stimulus control on all your behaviors and save unsafe behaviors for when you know your horse can handle not doing the behavior without the cue