I dunno if this only works on a certain device based on speed, but here is how I find chunk boundaries (without the use of chunks.dat):
I go into creative, and cycle between night and day. you will notice it lighting in a progressive circle of squares around you. cycle until you know where a corner of one of these squares is, fly down, and place a block. fly back into the air and fly to a place where this block is about 2/3 between you and the render distance. cycle the night and day. ajust the location of the block until it is in the perfect corner, then create a 16x16 square. this is your chunk.
This would be useful to control modding the generation to create, say, one pillar of 118 tall dirt in a normally generated world.
if you want a normally generated world, but you want one chunk to be superflat, follow these steps.
1. create your normal world. best in creative.
2. modify the chunks you do NOT want changed. to do this, simply place a block.
2a: to find chunks, use the method above.
3. get your world file onto a PC whether by USB cable or dropbox.
4. rename the world as a .zip and unpack.
5. rename project.xml as project.txt
6. open project.txt
7. go in and modify the terrain generation to flat and terrain generation height to whatever you want, as a multiple of 8
8. rename project.txt as project.xml
9. repeat steps 5-8 for project.bak instead, making sure that project.bak shows exact same changes as project.xml.
10. send your world file to a .zip folder, then rename as .scworld
11. using dropbox or USB cable, get world file to device
12. you will notice that all chunks except modified are flat and specified height. modify the flat chunks by placing a block, but modify only the chunks you want to be flat.
13.repeat steps 4-11, except change terrain generation back to normal and re-specify generation height to previous default.
14.you should have one (or however many modified chunks) as flat and the rest as normal if you followed these instructions.