I think this is my first post here, but I've been lurking around for some time soaking the know-how available here, but there are still some questions that I seek answers for.
I am regularly shooting BW with small format, using my OM gear and rangefinders, developing my film and occasional prints in the bathroom, but I still want something larger and slower. I decided to try large format to be able just to contact print the negatives (both from film and from paper negatives), and I intend to built my pinhole camera using the DIY method to get into LF processing before investing in a real LF camera.

Now to the questions - when building a camera - is it necessary to paint/cover the inside of the camera with a black non-reflective layer? (supposing the camera is built from heavy cardboard or plywood)

For the film pinhole I have ordered some filmholders from ebay - how can I ensure there are no light leaks in the opening for inserting the filmholder? Can I use some rubber sealing-thing I used recently for isolation of my windows?

How do you attach a DIY camera (a box, essentially) to a tripod?

Is there any method how to "compose" with a pinhole camera - supposing the "focal lenght" is not wide but more of "normal"?

Thank you in advance for all tips and answers.