I think if you want to find out if gluten is aggravating or causing your condition you really need to cut it out rather than just cut down icclemunchy.
Sorry, I know I'm sounding bossy now, so obviously feel free to ignore me (!) but it really isn't that hard to do, although I must admit our food spend has gone up.
The upside is that we're now all eating more healthily anyway, i.e. less pasta & pizza, more meat/fish & two veg type meals. And my DH has lost a whole stone in weight and now weighs the same as me. He's looking great on it. We eat A LOT of rice and potatoes, and occasionally gluten-free pasta sometimes too, which isn't that bad.
Breakfast is trickier, but he's settled on Greek Yoghurt, gluten-free granola and fruit/honey, which seems to be ok, and he eats a lot of Nak'd and Eat Natural bars as snacks - all quite sugary so may not be an option for you.
Porridge has a different type of gluten in it apparently, which some people are able to tolerate, but he is adamant he doesn't want to 'nix' his recovery so avoids that too. But perhaps you could start with just cutting out wheat gluten and see if that helps?
A quick google on the link between gluten and fybromyalgia brings up loads of pages and information, so if you don't want to take my word for it, have a read!
Again, sorry if this seems bossy - I feel very passionately about the subject having seen the change in him, that's all, and want to spread the word to help others!