I like my system, but it was modified (from the Major and Ben Systems) in ways that fit the way my brain works, so I’m biased. 
0-9 => vowel
00-99 => consonant-vowel (explained here)
000-999 => consonant-vowel-consonant (Ben System)
The reason I modified the system for 0-9 and 00-99 is because I wanted all images to have a one-syllable pronounciation. Other than that, I don’t think that it matters much.