In my wife s village near madang papua new guinea they always use pvc pipe for guttering on corrugated iron roofs.
Diy pvc pipe rain gutters.
The narrow strip is then cut into lengths and used to strap the gutter in position.
They say it can t be done but it sure can just watch and see.
Turn the handle on the ball valve that is located on your pvc gutter cleaner to the off position.
Install the gutter and run your 1 5 downspout with 90 degree or 45 degree depending on your configuration.
Clear your gutter of debris by starting near.
Then cut the top 1 3 to 1 2 of top of the pipe off.
A downspout would be very simple to make as well just simply glue in two end caps and a 3 x3 x1 5 tee to your 3 pvc pipe.