I though you might ask me that!
Ok, what you need is a copy of GameHack 2.0 (
http://www.telecable.es/personales/malvarez1/Files/gh20i.zip), this does not work on Windows 2000 BTW.
Here are the steps you need to follow:
1. Start ePSXe (or the emulator that you are using).
1a. Go to the Chocobo Forest in the game.
2. Start GameHack.
3. Click the button in the top left corner of the window.
4. Select your emulator in the Process List.
5. Start playing the Chocobo Digging game and pause the emulator.
6. Now click the Start Search button (on GameHack).
7. Select Advanced from the Search dropdown list.
8. Click the Ok button.
9. Carry on playing the Chocobo Digging game, pause the emulator once you have found an item.
10. Go back to GameHack and click the Next Search button.
11. Choose Increase from the Search dropdown list.
12. Click the Ok button, this may take some time.
13. You may get a 'Too many addresses' message, just click Ok.
14. Go back to step 9, do this as many times as you can within the time limit. If the timer runs out, you'll have to go back to step 6, so you have to be quick in the Chocobo game and pause the emulator as soon as you find an item.
Eventually you will find the address in memory where the emulator stores the value for the number of items you have collected so far. What you need to do now is double-click the address in the list (there should only be one) and it will appear in the bottom window. Just click the checkbox in the bottom window and a green smiley face will appear, this will indicate that that address is now locked to that value. You can then set this value to 5.
When you find your next item (when you start the Chocobo Digging game again), the game will think you have already collected 5 items, and will increase your chance of the next item you find, being a Chocograph.
This all sounds a bit complicated but I assure you it works, I will try this again tonight and see if I can find the right address for you (I'm not sure if this changes each time you start the emulator, the emulator might get loaded into a different area of memory each time it is run).
Oh, and I will post my save once I have found it.
Good luck!