The solution to this question is to go the store and bang out some balls with various clubs. If you are looking to replace a 220 yard 5 wood (for example) go to the store and see what type of hybrid gets you about that distance.
Their 17 degree hybrid is equivalent to 2 iron and 5 wood.
Their 20 degree hybrid is equivalent to 3 iron and 7 wood.
Their 23 degree hybrid is equivalent to 4 iron and 9 wood.
They've matched hybrids with irons of the same loft, but surely the hybrid will go a little further with its longer shaft and weightier head? The hybrid-wood match up strikes me as reasonable since the equivalent fairway has a higher/weaker loft which i guess would offset the effect of its longer shaft relative to the hybrid.