For my horses I show talk to them when I approach and then I show them the bottle. I usually rub it against their muzzles and let them smell it first. I also run my fingers over where I'm going to spray because if you do it light enough where they twitch it's a similar feeling to being sprayed and then I spray them
I would try by slowly approaching them, showing them the bottle so they can recognize the sound and feel that comes with it. I would also say to touch or rub the area before you spray so they are not as surprised. For the blind one, talk to them first and start by spraying the bottle away from them so they hear the noise and know what's coming. Hopefully over time they get used to, just keep a consistent pattern with them and let them know its going to be okay!