I like your idea of 30 practice, then 30 watching, then 30 practicing, back to watching again. If your fingers only last about 15 minutes now, then 30 minutes would be best. If your day limits your time always choose practice over watching.
Another thought, if you find yourself with 15+ minutes of free time and you’re not near your guitar, close your eyes and in your mind watch yourself practice. Watch your hand make the chords or play scales. Taking one day a week off can be useful also to let your mind work on things while you do other things.