I found on the net only the exact spawn rate for diamond:
DIAMOND: 0.1276% of stone from levels 2-16.
Someone has the other spawn rates?
Below row 14, Redstone-Ore can be found in 1.025% of stone.
From levels 2-28, gold ore's occurrence underground is at 0.1437%.
Ironis found in approximately 0.72% of stone from rows 2-61.
coal ore comprises about 1.25% of all stone, regardless of altitude.
Lapis is a bit tricky, but I guess you get it right.
Diamond is wrong, the amount is right, but only below 12 now, but I'm not quite sure about this one. Checked it in my world an no Diamond at 15 and 16 for sure, some at 13 my result in veins starting at 12 and expanding into 13. But the amount is correct and since you don't need diamonds for generators it doesn't matter either.
So since this is only one part, you need to value something different too. The requirements for over purposes. So just give things a value based on uses and frequency in which you find them.
We could be sure to widely ignore the need of coal, glass and rubber, since this are all ressources avaible to create extend, so they should only be weighted slightly. So let's just base Iron at 1. Copper should be 0,3 and Tin maybe 0,7. Redstone should be 0,5, since it is avaible quite easy mining a bit deeper isn't something that costs you anything. Lapis and Glowstone should be valued with 1 too. Coal and Rubber should just get 0,1 since they so incredible easy to get.
So basically a Windmill is 12 pieces of Iron, 2 Redstone, 4 Tin and a cable. Based on this evaluation it would be 12 + 1 + 2,8 + 0,25 (ignoring the furnace...). So it would get a score of 16,05. The watermill is just a halfed generator. So it is the windmill -4 Iron and you get two, which would be 6,025.
Your Windmills EU/t is horribly wrong. A windmill placed as high as possible (126, since if you place it at 128 and use two cables to connect it you land at 126) produces about 1,5 EU/t on average. I think if you choose a stormy region you could get a steady 2 EU/t, but since your windmill will most likely break not many people will do this. About 40.000 EU per day is the maximum you could expect from a windmill on regular basis. A normal Windmill placed at 80 (it will never break) produces 19.500 EU/d which should be around 0,8 EU/t. This is still better as the solars, but quite on par with the unmanned watermill. You should take this number for a "normal" windmill.