I tested the EG18 grenade today under nearly identical conditions: Wind was 3 mph from the WNW, temp was 86, humidity 93 percent. The cloud produced was nowhere near as dense or large as the EG18X. On a side note, there was a family walking by that were quite impressed by the smoke cloud.
In other news, I inquired about flash bangs, and the first place I asked provided this response:
Thank you for your interest in our product. Unfortunately, it is only available for professional use due to its restrictive nature and cannot be sold to the general consumer. This product is classified as a true pyrotechnic. As your reason for use mentioned airsoft, you may have seen and/or used our device at national airsoft events, however, those facilities and personnel were authorized and licensed for the use of pyrotechnics.
Since they class it as a “pyrotechnic” and not a destructive device, I am thinking there is a way to procure something. More research coming.