What is the length of the drip edge flashing?
It should be used with or without gutters. It protects the edge of the roof sheathing.
As per Specifications on product web page the gauge is 27
It is to cover the edge of the roofs plywood. It should not be listed as for windows.
Yes, you could just readjust each of gutter hangers when installed. See the photo. https://qph.ec.quoracdn.net/main-qimg-e370dbd9476f9b81da1f5ef20a975830-c
The front of the drip edge is 1" high so it would depend on how wide the nailing edge is.
There are 50 pieces per carton
This will not stop the rain from coming down in this area. I would suggest a Rain Diverter to be installed under shingle.
No only in 10' Lengths.