is it possible to change character limit in console?
It's not. If you want to do something really complicated, plop down a file called thing.lua next to TPT, save your complicated stuff there, and run dofile("thing.lua") in the console. If your stuff is complicated because it involves filtering and changing properties of particles a lot, I suggest you take a look at this script.
You can create autorun.lua file in tpt folder and put dofile commands (or the whole script) into it. So you will not need to type "dofile" each time.
Also (tested on android version) you can touch-and-drag the divider of scripts and logs (vertical line) to the right side. So you will have more space for commands but less for logs.