Questions on my new wallet project

Hey guys!

I'm working on my new project. It's going to be the most complex project for me so far..))

And I would be happy if you help me with some questions on this project.

I have a lot of questions, I'll try to solve them on my own, but anyway I think, I'll need your advice :)

I'm going to make a horizontal bifold wallet, 8 card pockets, 2 hidden pockets, 2 cash pockets. I’ll use Buttero leather 3-3.5 oz for whole project.

Since my English is not very good I decided to add images, to make my questions more clear :)

I'm still adjusting sizes.

On the first image, you can see layers of the wallet.

The first question:

When I attach the detail "B" to cover "A" should I bend cover before gluing detail "B" on it?(image 2 - 1) or it doesn’t matter and I can attach detail "B" on flat cover?(image 2 - 2) Detail "B" height is about 15mm.

The second question:

Detail "D" width is 245mm. How much longer should detail C and A be than detail D? I think to make "C" 10mm longer and "A" 20mm longer or should I adjust it by hands?

I'll add more questions later :)