Yes it is fine enough, it keeps the little blighters out no problem!
I took mine up to Morar in the middle of last month, there weren't a lot of midges around, but enough to know they were there. I only used the hammock once, I had a borrowed tent along and the area we were in had a lack of trees, but the on the morning I did use it, I had a close up view of a few dozen frustrated midges marching about on the outside unable to get in.
The velcro is also enough to keep them out. The only problem comes when getting into and out of the hammock, and then trying to dress. Trying to put on trousers and shirt while lying in a Hennessey could give less flexible members some real problems! Then again, that is always a problem in a hammock, its just that with midge waiting for you outside you become less keen on dressing in the open