uv unwrap using cylinder etc

hi

how is it possible in blender to unwrap an open cylinder in a way
that the faces are in correct proportions.

when i use cylinder the faces are all to long along the y axis!!!

just use constrained scaling to adjust it. also, when doing a cylinder unwrap, two things:
much of the time, you will find that some faces end up on the wrong side of the seam. go into active face select mode ( in the menu ), select those faces, manually drag them over to the other side, where they should fit, like a puzzle coming together, then, selecting them along with the immediately surrounding area, press the ‘v’ key to weld them into place.

the other thing, is, rather than trying to rearrange the top and bottom faces, which tend to overlap, just go into top view/bottom view, and map ‘from window’.

so, blenders cylinder unwrapping is probably not the best, but oh well.
the other alternative is to map in quadrants ‘from window’