Gallery management

Among countless posts about gallery issues, I wasn’t able to find the right answer.
I hope, once and for all to get a straight, suitable-for-all, answer.

Needed: add pictures in a gallery post.

How I do
SOLUTION A: create the post, set name and description, Upload/Insert the images from my disk, once done set gallery style and sort order (I need this options), update and publish.
What I get: two galleries. one with big thumbs in 3 columns (I want 4) and below that my actual gallery.
So: this not works.

SOLUTION B: as written as answer to some posts here, [gallery] short code is not supported so, from the Library, I attach pictures to the post.
What I get: now only one gallery but thumbs are too big and only in 3 columns.
So: I need one more column and the option to set a Date order.

Then: where and how can I operate a change in CSS/PHP in order to obtain that? Is it possible?

Thanks.