All right, seems I'm a bit too concerned then hehe, other than the struct size should be dividable through 4 on a 32bit system, to put it simple. So, whether a struct would be 28 or 32 bytes wouldn't matter in that case.
Yet, I've read (a long time ago) that the programmer chose for a specific (small) struct size in complex algorithms such as pathfinding, so it could be easily "cached"... I know why things are cached, but forgot how it exactly worked.
Delphi is not padding all structs in my case, since I specifically tell those structs to be "packed" in some cases. Usually in cases where the struct is also stored in a binary file to keep things compact and easier to predict.