I think I can answer this one, being a 4003 user with a 210 and a 212!
Are you using the 4003 in the classic "Ric" style, ie. shedloads of treble on bridge pickup? If so use the 210, it seems more sensitive to my ears for those treble frequencies you want to be prominent in your sound. If you are going for mid position or a full neck PU bass sound, try the 212. I generally go for the 210 with my sound, seems to fit it well (worth noting I use the Staccato '51 which has a bit more treble scoop in it anyway) but the 212 certainly wont let you down either.
Or better... get both and stack 'em