In addition to the explanation above, there’s a a related post here: How to format text in the forum
The draft of whatever you’re writing gets saved in your account as long as you’re connected to the Internet. You can find all your drafts here:
https://forum.artofmemory.com/my/activity/drafts
(The /my/ part of that URL will redirect to your own user account.)
The main purpose of the Dominic System is to make it easy to find initials that match the letter pairs.
7 is G because G is the 7th letter of the alphabet.
8 is H because H is the 8th letter of the alphabet.
The only three that fall outside of that pattern are:
0 — O: There isn’t a zeroth letter, so O is based on the similar shape.
6 — S: I suspect that it’s easier to find initials using S than F (the 6th letter of the alphabet)
9 — N: this might be easier than I (i) when dealing with initial letters.
It’s okay to change the number-letter assignments if you want. Here’s an example of how I modified letter-sound assignments from another system called the Ben System: A 2-Digit Consonant-Vowel Number System (CV System)
As long as you can remember the associations, I think it’s fine to modify them.