I know that by RAW, an unconscious creature regains consciousness when they regain any hit points through healing, or (if stable) they "naturally" regain 1 hit point and consciousness after 1d4 hours.

In game play, I came across a very specific situation in which characters chose to inflict non-lethal damage in order to knock an opponent unconscious and then wished to wake said opponent for questioning when the danger was passed, but they did not wish to expend any resources to heal the opponent or wait 1d4 hours for the opponent to wake naturally. I made a temporary ruling at the table, but have been brainstorming a "permanent" ruling should such a situation arise again. As a new DM, I am shy of homebrew and house rules, but I recognize that there is flexibility in the game for a reason.

Before we implement a ruling into our game play, I was hoping to gain some insight from those more experienced than myself. I have done some searching on the wonderful wide world of the internet, but have not found what I was looking for (operator error is entirely possible). In creating a ruling, my intention was to remain as close to the RAW parameters of the game as possible, and use similar RAW actions or abilities to define the specifics, while still allowing for the questioning scenario. Here is the house rule I have tentatively developed:

"A stable unconscious creature can be woken temporarily without receiving healing and before 1d4 hours naturally restores it to 1 hit point and consciousness. This can be accomplished through a successful DC 10 Wisdom (Medicine) check or expending one use of a Healer’s Kit. If a stable unconscious creature is woken in this manner, it remains at 0 hit points but regains consciousness for 10 minutes. During this time, the creature has its full mental faculties and can speak and make simple gestures (within the limits of its traits) but cannot move, attack, or cast spells. After 10 minutes, it relapses into unconsciousness and cannot be woken again in this manner; it can regain consciousness again only through healing or after 1d4 hours naturally restore it to 1 hit point and consciousness."

So, has anyone used something similar? What do you think?

You can just say to them 'shake him to wake him', as raw, an unconscious creature can be woken. Dead and unconscious are different. You can make the npc not die, and so the shake awake rule works. Most DMs (and the official rulebooks) say that the DM can decide to make an NPC not die, as most don't get given death saving throws.