Aggie:

I didn’t mean to rain on your parade (hard to do in S. Ca., but that’s all we have had in the Eastern Swamp this year). But since I retired from R&D and came out into the real world, it has seemed to me that every time the term “chemical” is used, all souls become nervous and guarded.
You certainly are doing some good explaining the design for a “normal” hood. When I first saw your proposal, My mind went into overdrive thinking “glove-box” – a particularly demonic device perpetrated by management to curtail initiative and efficiency (if you ever had to work in one, you know – or a “clean” room).
So again, good luck and maybe a photo in the off-topic gallery?

Truly, dr bob.