I travel a lot for work, so I use 2 setups. Dual Monitors at home (preferred) and 5 on my 17" laptop screen on the road. For the laptop I use a 1920x1080 main region (full resolution is 1920x1200) with the slaves at the top left using 304x171.
I'd recommend getting another monitor if its an option, but keeping them all on 1 really isn't bad. Just be sure to select "Slave regions always on top" for some nice PiP if you go that route.