I just noticed your charts and all your hard work. Let me just say that I think fresh grass (which we can't find good data for) is one of the best things you can feed your guinea pig. Start slowly if they aren't used to it. I used to feed fresh grass year-round. Even brushed off the snow and picked grass in the winter.
I think your charts give a new way of looking at foods and reiterate some guidelines that are handy to follow -- like how fruit should be fed sparingly and crucifers can cause gas. A pig that is acclimated to crucifers may have absolutely no problems though. Because we don't always know what causes gas buildup in the cecum (not a frequent problem but can be serious if it turns into bloat), I guess we have fallen into recommending to give it sparingly.
Keep in mind that when you are feeding foods, you want to aim for a balance of things. Heavier on the leafy greens, lighter on the fruits but include variety. A veg high in calcium can be offset by a suitable food low in calcium. For any of you who have a good scale and excel installed on your computer (you can also use
http://www.openoffice.org/ which is free), you can see how your pig's diet stacks up on calcium and phosphorus here:
http://www.guinealynx.info/calculator.xls
And hay. 24-7, have a high quality grass hay available. This is so important for your guinea pigs.
I think each person works out what to feed their pig based on what is available and what their pig likes. Go easy on carrots and fruits but bits are certainly okay.