Interesting. My 70% shade cloth, and it is 70%, does not sag, does not channel water, nor does it trap heat.
I have it over a pergola on a deck here in Massachusetts
and it works just fine for me, and has been for the past 4 years. By the way. NE could be New England also.
I was thinking NE was North East, but either way, it wouldn't really change the fact that it's a summer only shelter.
Anyway, most monsoonal tropical orchids have a shadier summer than winter due to the cloud cover during rainy season(assuming of course the monsoon is during summer, since there are monsoonal areas that are reversed). Plus the leaf cover is also higher in summer than winter.