First of all your tolerance is NOT very high at all. ~40 mg of hydrocodone (vicoden) is not a lot, comparatively speaking. Anyway, 5 vicoden 7.5s = 37.5 mg. According to the opiate conversion program, that is equivalent to 187.50 mg of Codeine (oral). It is not 100% exact, but these converters will help you get a pretty decent ballpark estimate.
The codeine high may not feel quite as good as vicoden, but i would recommend starting off with a 150 mg dose, just to make sure you aren't allergic, and also because it is better to start small, rather than take too much ( Like you did with the darvocet, an incredibly crappy and dangerous drug ; throw them in the toilet ). See how you react to that dose, and if it isn't enough wait until another day, and try 200 mg.
Also, codeine has a ceiling effect. The "average" ceiling is 400-500mg. You may be different; It depends on the individual. The ceiling dose means that the liver can only convert that amount to morphine, which makes codeine active. If one were to redose more than the ceiling, there would be no effects to follow.