I'd imagine it's along the same lines as my Force Male Gender patch, but I don't really want to take the time to see how to do it right now. I'm hacking GBA Wonder Cards, in fact.
I tried writing the bytes directly to RAM using the memory viewer, and it didn't do anything. Therefore I have my doubts about it working in a script, but I'll try it soon and see what happens.
Yeah, that's how the hack works, it reads the data from the block immediately after to use as the third layer, making the second one simply unused... Don't tell me you put two random blocks that each had 30 set...?