What about instead using a little base 2 to memorize? So 'b' can follow 'a' or 'o' and be followed by 'a', 'e', 'i' or 'o'. Take a as 16, e as 8, i as 4, o as 2 and u as 1. So if you memorized '18b30' you could decode that in your mind to the right combinations for 'b'. Obviously this doesn't work for the combinations with two consonants and the words ending in 'y', but it's a start. I think you'd pretty quickly learn common values like 30 is 'aeio'.