I have my roms in /mnt/card/roms/znester/
so in /home/Qtpalmtop/bin I have a script for example Dkong.sh as follows
#!/bin/sh
export S9XKEYS=27,100,99,115,120,97,122,13,32,103,106,117,110,121,98,105,109
export S9XKEYS=27,290,291,292,294,293,122,13,32,103,106,117,110,121,98,105,109
export SDL_ROTATION_QTE=0
export SDL_ROTATION_SDL=0
znester /mnt/card/roms/znester/DonkeyKong.nes
Don't know how to fix it with zemu but this script works to fix the keys
Also don't know how to make it bigger on the screen
Obviously you need a new script for each rom.