Hello M_31:
I guess that style is a matter of the beholder like beauty, for me rain gutters falls a little short though some folks might find the rain gutter solution satisfactory.
The important numbers as you said are the tank length and light fixture size. Get your numbers together and go to the local hvac fabricator to make the hood then, if you don’t wish to do it yourself.
All you do is take a one dimensional lay-out and use it to make a three dimensional object that exist in time and space.
A one-half dimensional man,
pop
