Vents and Drain for Hydro Test

I think you need to restate your question. The way you have written it is confusing.

However I will offer this:

1- A High Point Vent must be at a high point.

2- A low point drain must be at a low point.

3- Can you put either one on an elbow? That depends on a lot of things including whether or not your Client has any specific objections.