You’re OGS 3k. I expect that with some practice you can give 6-7 handicap to raw novices on 9x9 (like @richyfourtytwo).
If that is the case, and you use a factor of 4 ranks per handicap stone on 9x9, those raw novices would be ranked at about 27k. Do you feel this is about right for raw novices, or is it too high/low?
On 19x19, I’ll go as far as 17 stones.
Here are two slow IRL 13 handicap games against an adult player whose level I’d estimate at about 15k EGF at that time, based on games like these (he’s much stronger than a raw novice, he can probably give 13+ stones handicap himself to a raw novice on 19x19):
With the factors I use in our club, I would give him 5-6 stones on 13x13 and 3 stones on 9x9. The factors I use are 6 for 9x9, 3 for 13x13 and 1 for 19x19.
In my (children’s) club most games are played on 9x9, 2nd is 13x13 and 19x19 is a distant 3rd. Only a few of the players are stronger than about 20k and willing to spend more than some 10 minutes on a single game.
On 9x9 I give the strongest players (about 15k) 3-4 handicap and they give 5 handicap to raw novices (who get 8 handicap against me).
Edit: The games I linked are 13 stones handicap, not 17. I adjusted the numbers accordingly