No, seriously dude.
Take as long as you need. Rushing gives it less quality.
Like if your cooking in the oven. You'd wait the full 20 mins. Not wam the power up to full and wait 5 mins.
... right? (... mmmm fooood xD)
Okay, i finished the trees,grass,and mountain, (it shouldn't have taken this long) but i got it done, i'll show you a pic first to see if you like the new tiles, if not, i'll add new tiles to fit better the palletes.