How to put data in VRAM

[alekmaul]

Could you make a wiki page that explains where it's better to place the data of sprites and bgs in the VRAM,
I saw some pointers must be 4k aligned, other 8k - X.
If I am in mode 1, where do I put the sprites in the VRAM, at 0 or at 4096 or at 8096-2048?
BG1 : at 2048? or 1024?
BG2 : at 2048 + 2048? or 2048 + 1024? or 1024 + 1024?
I just don't know, some combinations work, some don't. There is no documentation.