Here's an interesting chart linking consonants to numbers in an aid to create mnemonic devices. You have to scroll around half way down the page.
I find the concept really interesting, and I can imagine after a while it could really become second nature (like shorthand) but I'm not too happy with the 'r' being there. 'r' is not a stable consonant, especially when it is used at the end of words like "care" or "par". You can also see that the sounds are paired phonetically with their soft counterparts just like in Gregg (eg. p,b f,v sh,ch,,j t,d s,z).