I would hope with persistence and determination, and a little patience an inch is very possible. Just be sure to take it slow.
I think the only thing I would purchase, if I was you; would be monkeybars Auto xleeve, with the yellow and blue sleeves. Get the regular and 5.5 oz caps.
Do the morning routine; and then put the blue sleeve and weighted cap on during the day, while you’re at your job. Do a smaller routine at night before you go to bed, and then go to sleep with the yellow sleeve and regular cap on. I’ve got a friend in a similar situation of working and stealth PE. The gains might be a little slower, but at the same time; your penis’s resistance to stretching wont go up as fast either. Good luck