I don't have fibro, but do have lots of nerve pain, and neuropathy in both feet (from spinal nerve compression, not diabetes). I take percocet also (about the same dose except I'm still taking 2 - 5mg tabs), and neurontin - 400mg, 4X/day. I had to start the neurontin very slowly a couple of years ago - had to go to 100mg tablets, and finally worked myself up to the current dose. I do believe it makes me groggy, although I've adapted somewhat to it. I've actually tried lyrica but only in small doses and never had a doc who seemed to understand how to dose it properly, as it's fairly new. Still, you're on a low dose from all I know.
The only thing I would wonder is whether you could take the lyrica once/day. I don't know what the half life is. I have read 2x/day is not an uncommon schedule. Not sure how neurontin would work, but from what my cousin (a pharmacist) tells me they're similar, but the lyrica is supposed to have fewer side effects. Like you, if I cut back on the neurontin, or am even late on a dose, I know it - especially in my feet! How experienced is your doc in dealing with lyrica? I'd try to find a doc or pharmacist who has dealt with it frequently and see what kind of dosing they suggest. If you've never tried, neurontin, it might be worth it, but you may have to go up slow.
This is so challenging, isn't it?!! I wish I had more to offer.
p.s. I'd also suggest going directly to the manufacturer's website for lyrica and read about dosing, etc. for yourself. I know it's full of technical stuff, but you may pick up some ideas.