Generally, warm white lets through about 10% of the blue, natural/soft/outdoor white lets though about 20% and cool white lets through 25-30%.
That can all change from one name brand to the next, but it is an average.
If it makes up 17% in diodes used, that really does not mean anything other than 17% of the diodes.
Here is a chart I made using Excel and data from 100w Cree XPG warm white, 6w of Cree XPE royal blue, and 10w Philips Rebel deep red.
As you can see, it only takes 6w of blue to make a similar amounts that the whites do.
And here's one more chart showing 100w of Cree XPG cool white and 15w of Cree XPE royal blue.
As for the 660nm, I think some plants can use it more than others, and levels
of varies as well.
I think it depends on the genetics of the plant(s) grown, and where those genetics are from in the world.
I am a firm believer that plants like a full spectrum, after all they've been growing and evolving under a full spectrum for millions of years.
That is why some panels that have too much 660nm (mine are less than 25% deep red in the 2012 models) will be hit and miss from strain to strain.
My newest panels will have mostly Cree XPG Outdoor White, and a small boost from Cree XPE 630nm. I could have chosen to put deep red, but I do not believe they are necessary at this point with that much white. For plants that like deep red, they can get their 660nm fix from the whites.