[Other] Question about overwriting data/writing to ROM

[EndercreeperMugen]

A relatively simple question, likely with an answer I'm just too stupid to see. So, let's say I've already replaced a Pok?mon's sprites, but I now want to change these sprites to better-looking versions. How safe would it be to overwrite the already overwritten offsets? Or does the "it's OK as long as there's free space" mechanic still apply?
Oh, whilst I'm here, I also need to ask how I'd change which Pok?mon roams Hoenn after beating the Elite Four? I accidentally got Latias and Latios mixed-up when swapping them out for the new pair of Pok?mon. Thanks.

 

[Sakib66]

Overwriting can cause issue.....Since you have free space, I don't know see a reason to overwrite .

 

[EndercreeperMugen]

Overwriting can cause issue.....Since you have free space, I don't know see a reason to overwrite .

Well... I suppose I could always create a backup before overwriting. Wouldn't want to mess-up my 5 months of work to a state of disrepair.

 

[Blah]

It's fine to overwrite. Make sure to pad the new sprites to be 2048 bytes.