Yes, I do actually. I wrote a nice documentation on it in fact: http://www.pokecommunity.com/showthread.php?t=236456
It uses the game's basic animation system, so it's pretty simple. To extend the table, you can just repeat the same pointer as before for each new trainer sprite you're adding.
Not everything from 900000 to 96FFFF is used, but thats the space I will utilise.
907000 is eventually going to be used by further move effects and battle scripts.
If you want to add anything new, start at 970000.
Oh right! Uh yeah I guess applying my patch, and then putting JPans thing again, should be fine. I haven't tested that but I guess it makes sense. It's not just the deleting, if you have changed the map sizes and the map names it might prevent the thing from being read in advancemap. My recommendation would just be to start again, and copy the maps and things over into the new rom.
If you had not used Jpan's thing you could probably have used it.
My patch only works with Jpan's engine if you apply my hack FIRST. Because my thing decapitalises the scripts, so because the scripts are removed and where they were is now code, bits of it will be overwritten with decapitalised words.
What do you mean by offsets that are affected? The only things that are changed are moves, abilities, type information etc.
Basically all the patch information is in the region 900000-96FFFF
It doesn't change trainer or sprite offsets back to the vanilla ones, it just changes the default Fire Red text.
Patches don't work by being able to choose where to put offsets, it would need a custom tool and would require a LOT of repointing even in the tool (which I wouldn't
be able to program anyway) due to the nature of battle scripts and ASM abilities.