For reality checks, I do them when I remember. Its the same thing, sometimes I do them 5 times in an hour. And sometimes 5 times for 5 hours.
The thing it helped me is that I always do them when something seems strange to me.
Also the thing that might help you analyze your dreams. If most of them occur in a building, do reality checks when ever you pass thru a door. If you dream of some friend often, do a RC when you think of them. And so on..

For the second problem it all depends on your goal. If you want to wake up easier at 7am you will need first to change the time you go to sleep.
Until a month ago I was staying up every night till 3am. Then I would go to bed, wake up at 12pm, and I was exhausted.
Now since I've been doing some organizing of my life, I started going to bed before midnight. First I was setting up my alarm clock at 9am, but after three days I started waking up before it.

6-8 hours of sleep is more then enough for a person of your age.
But this means going to bed at before midnight. And this also goes for weekends too. It will be hard at start, but when you adjust it will be easier and you will have more energy.
Also, you cant achieve this by doing it 5 days a week and then for weekends to sleep in late.

Some sacrifices must be made, the question is are you willing to do them and do you find it worthy...