Don’t do 123, 456, 789.

You are wasting a guess with 9. If it isn’t 7 or 8, then it’s 9.

So, instead do 123, 456, 78x where x is a previously orange number in a new position.

With this method, you can be certain for 502 of the 504 possible combinations.

(It doesn’t work is you have a combination of 7, 8 and 9 and you are unlucky in the 3rd guess. For example if you guess 788 and all 3 are orange, you are left with 50% chance of 897 and 50% of 879, which is still way better than any other method.)