It really isn't that bad in August. I have been down to Roatan for the past few Augusts and never felt uncomfortable, even in the AKR casitas that don't have air conditioning. I would concur with Dee re avoiding rainy season of late September, October, and early November - it is just too unpredictable and, overall, too much rain!
Can't get into CoCoView? Thought about AKR? The west end location gives you good chance of a whale shark encounter in August, when they tend to pass between Roatan and Utila!
After countless trips to the Bay Islands, I am wondering if the no-see-um issue isn't which bug repellant (Catcus Juice, Skin-So-Soft, Deep Woods, or some DEET concentration), but rather a combination of:
1. Individual differences in body chemistry/scent (many times I've seen two people can use identical lotions and one person gets nailed while the other has no problems; or even more aggravating, the person drowning in DEET gets nailed while a person who doesn't bother with anything gets off without a bite).
2. Compulsiveness in lotion application.
3. IgE/allergic response (two people both get bit, but only one explodes with the red welts).
Don't be daunted by the no-see-ums. The no-see-ums and the pursuit of the perfect repellant are just another social lubricant in meeting other diving enthusiasts sharing the beauty of the Bay Islands.