Hi Stan, sorry for the delay!

I'm working just these days on a video where I'll also talk about how to manage the size of the character according to the proportions of the map visible on the screen. So at the moment, I can only tell you that using a sprite half the size of the standard one will get the result you're looking for. For the jump ability, try using the Galv Jump Ability plugin, which allows you to jump a certain number of tiles. 

I hope I have helped you in some way! ;)