I use the same stuff. Take it every 8 hours. The only problem with the minoxidil 5%/alazaic acid5% mix is after it dries, if you touch your hair it will turn into a white powder. This will happen even from taking off a shirt. You'll look like someone dumped baby powder in your hair.
What I found is if you use a little hair gel a few minutes after applying the mix, it will help stop this from happening.
Even though your goal is to get as much on your scalp as possible, inevitably some will get on your hair. Especially if you keep is kinda short. Just make several parts in your hair and spray. That’s it.